The problem with this is that in most of the tests were Jayant has played, one of the pacers has usually been a complete passenger. Umesh barely bowled in one of the games. It's just a waste of a spot. If you're going to go with 5 bowlers and one of them is hardly given a meaningful number of overs, it's a pointless strategy. You can get much more value by adding another batsman instead.
But if the lone pacer you have gets a niggle, for eg Shami, you are pretty much screwed in the fast bowling department, whereas having two provides cover.. and pitches recently have had a bit of assistance for the faster bowlers, particularly the uneven bounce has caused enough trouble against the pacers..
Jayant can average 25+ with bat and do a handy job with ball, which in total clearly outweighs the potential 40+ avg by Nair.
But yes compared to a faster man like Umesh, it's arguably better to play Nair, however, I'd still have Umesh in case the wicket ends up having assistance for the faster bowlers and/or there's reverse swing.. plus the guy can consistently bowl in the mid 140s along with Shami.
In large majority of the innings, you'd find at least one bowler out of 4 or 5 bowlers not bowling well.. and if it happens to be Ashwin, you have Jayant who can contribute or if it happens to be Shami, you want to have someone else to go to like Umesh or Bhuvi who can step it up.. That way, it's a complete bowling unit, covered for most scenarios and contingencies and it's more effective as the faster bowlers can have quick sharp bursts.. It's worked wonderfully so far. The two games where England scored a lot were the 1st & the last game where the 5th bowler was the undesirable Mishra...who didn't cover up for below par Ashwin. I'd take a batsman over Mishra almost everytime.
The batting does appear not as solid with 5 bowlers but there's depth to compensate for that, and you want to win, especially when you are expected to win every game against the Aussies, so any defensive approach like lengthening the batting at expense of bowling should be avoided, unless it's a bunsen. But we are unlikely to get any bunsen with Kumble the head coach & with India having already done well on good pitches. It's only if India lose on a good pitch, will they consider a big turner..otherwise we are bound to get pitches which are good for batting first-up, which once again points towards 5 bowler strategy..
Karun Nair is a spud anyway with clear weaknesses. If Shami is unfit, then it will not be ideal to play someone like Ishant who seemed to have lost the edge after his illness..
