Better standard of competition. Apart from the big 3, the likes of Dortmund, Fiorentina, Anderlecht and Napoli are as good as any team in the CL. Astana, BATE Bor, Tel-Aviv - you get all the glamour clubs in the CL!
Not playing on Thursdays. The only difference it makes is that fans don't drink as much on Sundays cf Saturdays, which affects the atmosphere.
No last round of 32. Agree - this is the one big flaw
No World Cup dropouts. Related to the last point - this is why there's that round
More revenue generated for the club. Mostly eaten up in extra costs (salary bonuses etc)
More exposure for the club than playing in the EL. I don't think this is the case since it has all moved to PPV. Now you don't get any casual fans watching games
The prospect of attracting better players to the club. Only the English belittle the EL. The EL is a big draw for most European players.