40 VP per boss amounts to 640 from raids per week. Clearing all the raid bosses in a tier should cap your VP. Any raider capable of clearing all the bosses every week deserves not to be forced into other content to cap their VP.
I don't want to run LFR.
I don't want to run 5mans (though I do enjoy challenge modes (which if you do the daily are quite rewarding in terms of VP)).
I don't want to do dailys.
I am a raider. I want to raid to progress but thanks to the iLvl upgrade system I am forced to VP cap every week if I want the bonuses it provide -- a system which is more mandatory than any shoulder/head enchant and more time consuming (and never ending).
TLDR; 40 VP isn't enough. Raiders should be able to VP cap from raids.
P.S. Allow 25mans to VP cap from raiding only, and you give a non-game-breaking bonus to them... something to offset the extra time it takes to maintain/run/organize them.