Oh lord, where do I start...
Okay, so you're doing two revisions every year - and by "revisions" I'm thinking you mean SB,IB,Haswell. Can you image the hassle that'd cause everyone with different "mainstream" SKU's every six months - not good for manufacturers or resellers.
Then there's the small matter of testing - with two rev's a year, what do you think the chances are of another Pentium bug type issue? A lot higher than now I'd suggest. You also can't guarantee board support - so your "Q2 2015" Haswell++ might have the same socket as today's 4770k's but your fancy Asus mobo may have to be replaced anyway. I've been caught in the past like that.