I think IIMA 's policy this time is still a good one! Atleast everyone has a chance..
Last year, as it was a 21 point system, it was a compulsion to score 21 or above just to be 'eligible' for IIMA. (which is a really high academic weight age and only those having excellent numbers on paper/mark sheet were in the race.) Still the cutoff was 99.4 %ile.
And IIMA had 540 calls for 400 seats, (ratio - 1.35:1, which is as big as 1:5 for FMS, and 1:8 for every other IIM. eg- IIM Indore had 3900 calls for 450 seats

)
Simply going by the logic, IIMA calls very less no. of students...thus it most probably will get more than enough no. of students with 99.5%ile in CAT and 27+ in AR!!! So, the cutoff mark (in AR) shall be there itself where it simply starts...

Plus two sections will more than obviously increase OA cutoffs, as it is evident from what CAT 2011 Convener said when asked about the 2-section system : "There are a lot of students who loose out a seat due to low score in 1 section" (They dont want to lose students clearing OA cutoff and losing out in 1 section)
Anyways..my rating is 18!!(OBC)

Dont know how to rate my rating
