I don't know of anyone, other than the architects, who would disagree with you. KSS came up with some PR flimflam about the stadium's form reflecting Spurs' "flowing" football.* Truth is, they just wanted the stadium to look architecturally interesting (though hardly original). And they were also conforming to current thinking about optimising viewing distances. Obviously, fans in the upper corners will be further away from the action than fans in any other part of the stadium.
But fans don't really care whether or not the interior of a stadium looks architecturally interesting. Nor, within reason, do they care about viewing distances. It's not as if the seats towards the bottom of the upper tier corners are so very much closer to the pitch than any seats towards the top of the upper tier corners would have been had they been included in the design. In fact, seats in the very upper corners would be a perfect opportunity to offer tickets at slightly cheaper prices.
For me, the sharply dipping corners in the current design have an emasculating effect. They dissipate the sense of it being a bear pit. They relieve the mild claustrophobic effect that all great stadiums impart.
Probably wishful thinking, all too sadly, but I'm hoping that the proposed capacity increase redesign will see the dipping corners filled in, at least to some extent.
* If we're going down that line, then the predominant design theme should be triangles, surely? Triangles are what Push And Run is based on, after all!