Believe it or not, that's the short version. Anyway, that's our formation. The Sandro + Modric + Parker midfield completely destroys that.
Before I get into exactly why the midfield combination destroys it, I'd just like to remind you that City were boring boring City for playing 2 strict DMs (De Jong and Barry), even playing Milner and Yaya Toure as deep midfielders would make a 2 DM system much more dynamic than that 3 deep midfielder system. I'm not saying Modric is deployed as a strict DM but he is a deep CM. Emirates Marketing Project like a 4 3 (2 deep 1 offensive triangle) 3, it lets both of their full backs get forward at the same time, they play 3 forwards and when they don't play 2 pure destroyers, they do have a sort of balance.
With those 3 midfielders Harry plays a 4-5-1. VDV is out of position on the right, it is madness to expect Bale, VDV and Ade to be able to create anywhere near as many chances in that system, even with Modric trying to find them with passes. Walker ends up having to provide all the width on the right and Bale removes all our width on the left when he roams. Our entire attack has one added step to it.
Usually our build up is quick and focuses on unleashing a winger or a quick pass/flurry of passes through the middle. We also have an incredible counter attacking threat. Switching Lennon for Sandro does not add to that counter attacking threat, moving VDV from his best position to the right wing is a downgrade defensively and is unbalancing offensively. But that step this formation adds is simple: CB > Parker or Sandro > Modric > Winger or Ade. Finding Modric is now a key step. Sure, Sandro or Parker might be able to pass to a full back that might be able to pass to a winger, but that's still one extra step. Not to mention VDV is not a "winger" in the same sense that Lennon is. He isn't going to fly down the pitch at light speed... If we want a right sided player to fly down the pitch at light speed, it has to be Walker, so he has to run a hell of a long way to get to where Lennon would be, then has to run even more after already having ran a ton. The time lost and the fact Walker doesn't have Lennon's control/crossing ability and won't have VDV overlapping all the time means this is much harder than it needed to be.
If the opposition don't give Modric space, our entire strategy is screwed unless Sandro and Parker are capable of making a run forward (with or without using passes), in that situation it's got to be asked what they are there for. If we wanted an offensive midfielder, we could have played one. That extra step of having to find Modric and hoping he isn't marked is going to cost us if the opposition manager has even the slightest bit of tactical awareness. (Even if he doesn't, Modric is on the radar of everyone that plays against us, so a lazy way of playing against someone is to try to stop their best players and hoping for the best, this formation even comes apart against even the weakest opposition tactics.)
With the exception of King, putting 2 CBs alongside Sandro and Parker means that 5 of our 11 players will rely on someone else to get our attacks started.
I will slightly exaggerate something in order to get my point across:
..........................Friedel
.....Walker........Dawson.....Dawson....BAE
.......VDV...Dawson...Modric...Dawson...Bale
.............................Ade
What is that team supposed to do? It's a formation set up to try and win the ball back but why give it away so much to begin with? When that team gets the ball back, it isn't going to keep it and it isn't even going to have the meaningful possession of a stronger technical side.
To further illustrate my point, here are two extremes:
.......................Dawson (GK)
Dawson.....Dawson..(C).....Dawson...Dawson
Dawson....Dawson...Dawson...Dawson...Dawson
..........................Dawson
.........................Xavi (GK)
..Xavi.............Xavi..........Xavi..........Xavi
..............Xavi.......Xavi..(C)......Xavi
........Xavi...............Xavi................Xavi
As much as I love Dawson and think he'd make a better goalkeeper than Xavi, I think the second team would be far harder to play against. If you're thinking "that's not fair, Xavi is a better player", you're right, that's sort of the point. Sandro and Parker are good players, but they're not world class passers, against the weaker teams, we don't need that kind of destructive power. Against the stronger teams, we need people that can play the ball. 1 Destroyer is fair enough, they can usually find a safe pass, but don't rely on destroyers to form the core of your midfield, if a team presses Parker, Sandro, Kaboul, Gallas and Friedel, Gallas is the only one that wouldn't panic. Freidel would play it safe at hoof it (long, not to a winnable aerial battle with a short full back or something, but to one of their CBs), but we wouldn't have possession. If they tried to contain instead of pressing, we'd have to find Modric in order to play the ball forward meaningfully.
Just to compare with my opening 4-4-1-1 here is the 4-5-1.
.........................................Friedel
Walker......................Kaboul...............King...................BAE
......v.........................................................................v
......v.........................................................................v
.............................^..........................^
.............................^..............^..........^
............VDV........Sandro........Modric....Parker..........Bale
...............\..............................v............................v
................\...........................................................v
..........................................Ade
No counter attack is going to hurt us, this might be a nice "shut up shop" formation but VDV isn't going to track someone like Baines, Lennon would and he'd add width too, but with personal changes you could throw Hudds in the middle and this formation wouldn't suck as bad either. Still, with these players, the major pro is that the middle of the pitch is packed. (That's the con when we attack btw.) If a team uses wing play, our 4-4-1-1 wing play, they rip this team apart by bypassing the middle of the park. This formation is easy to defend against, Bale, VDV and Ade are the goal threats. Modric, Walker and BAE are the secondary threats used in build up play (but not actually likely to directly assist often as the goal threats), Sandro and Parker are the stand out weak links offensively. This team includes King because the 4-4-1-1 included him, I want to be fair, having King will strengthen this team when pressed and will offer one fast ball in front of BAE, and one ball in front of either winger.
VDV will come inside, our right side is narrow, Walker has to do a lot more work to make us look like we have two wings. If Modric wants to play a one-two through midfield he must use Sandro or Parker unless Bale is inside (if he is, we have no wings).... We're wasting a position. VDV is going to play just in front of Sandro, Sandro will defensively cover for him on the right wing and will try to defensively cover Walker too.
You don't even need many defensively minded outfield players to stop this. I know RBs and LBs tuck inside and offer cover for CBs against a 4-4-2, but Bale and VDV are too dangerous to be left to wingers, this formation uses 1 striker, so the 2 CBs should be able to take care of him. RB and LB look after VDV and Bale, 1 midfielder makes sure Modric never has space, make wingers aware of Walker and BAE as they are the only other attacking players in this system.
It's not an offensive formation, it is a defensive one. Defensively, it's good if you need to dedicate 1 DM to man marking Messi and 1 DM to destroy or mark the space in front of your box. If we were playing Barca and used all three deep midfielders for something defensively (which would make sense, Modric doesn't have to be able to tackle as well as Sandro or Parker, but he can tackle well anyway), you have a system that would offer some pros defensively. I think it'd have some serious flaws, Alves would make Bale track back and would remove all our counter attacking threat, VDV would have to come inside to make up for Sandro marking Messi, or because when Messi drops deep, they have 4 men in the middle of the pitch, which they also have when Pique joins the midfield.
To be honest, I feel that the 4-5-1 wouldn't hold out defensively against Barca for a ton of reasons, but I can only see its use as a defensive formation, so I'm trying to highlight the few good points I can see. I know this has been a long post, so I don't want to stray too much, but we believe we can beat everyone in the Premier League, we believe we can beat them relying on our offense rather than our defence. So what is this 4-5-1 for? Harry doesn't play VDV and Bale as forwards, so it's not a 4-3-3, the fact that Sandro + Modric + Parker in the same team have never given us a good offensive performance in this formation leaves me wondering if Harry plays this purely because Sandro is one of our better subs. Hudds is injured and earlier in the season people were debating Parker vs Sandro, so perhaps Harry considers him our 12th best player?