God Kohli is such a rubbish on-field captain. To be wasting a talent like Sundar by bowling him only 2 economical overs and batting him at 3 is just extraordinary. Batting AB at 5 might have worked so far as he's so good in any position and can hit 4s/6s at will, but long-term I think this is overly-funky and counterproductive
On AB I like him at 4 but don't mind him at 5 too much in this setup, however whilst I think Sundar higher up was worth a go it hasn't really worked the 2 times its been tried. This might be controversial but put Kohli at 3 and open with Azharudeen and Paddikkal. Don't know much about Azharudeen but sounds like he's a solid option who can get us off to brisk starts if not win games for us on his own. I also slightly worry for AB's back if he is keeping throughout the season, Azharudeen has 8 stumpings in 22 FC games so that would suggest he's a capable keeper. Also improves our outfielding massively if you have AB patrolling the ropes in the latter overs.
Then go with a lineup of: Azharudeen (wk), Paddikal, Kohli, Maxwell, de Villiers, Christian, Sundar, Jamieson, Harshal, Siraj, Chahal
Gives us 5 out and out bowling options and Christian has bowled in each of his 3 appearances for RCB so far so if we are going to bowl him when we have 8 bowling options it suggests we probably have one spin option too many. Maxwell very capable of bowling a couple overs on slower surfaces too if need be. Think if you are going to have AB at 5 you should have both openers play with freedom but at times feels like Kohli still wants to be that anchor. If he isn't going to maximise the powerplay I'd prefer someone else try to and Kohli can still strike at 128 as he has been doing so far this season from number 3.
ideal situation for me is De Villiers comes in at around 11 overs mark - a time that maximises his chances of batting at the death but also gives him time where he doesn't have to go for big shots from ball 1. at 11 overs that is 54 balls remaining, if de Villiers bats out the remaining overs he will end up taking over half the remaining balls at 32/33 balls most often. With him at 5 you might sometimes get him coming in later but as long as the team are flourishing that's 'fine' I guess - the top 4 can play with more freedom when you've got AB at 5 so if they aren't losing too many wickets you'd hope they are scoring pretty quickly and thus being less reliant on AB which wouldn't be a bad thing!
Not many can do what de Villiers can in the back end of an innings whereas I think you've got more players who can do what de Villiers tends to do in the early/middle overs - Ishan, Suryakumar, Samson, Pant, Rahul (until last couple years)