Jadeja and Ashwin still have a role to play for India in Tests (especially at home) otherwise they'll start losing them as well, removing them would mean that you shot yourself in the foot. Jadeja's batting in ODI's however is non-existent, there's nothing threatening about it and he gives the persona as if he's a dangerous lower order hitter when he ain't. One of my Indian mates from uni told me Imad Wasim is a poor mans Jadeja but the former is a much better batsman in ODI's even though he's got holes in his game, Jadeja isn't someone you can bank on in the lower order whereas Pandya can propel you to big totals.
Ashwin on the other hand is a pedigree Offspinner but I personally think he's just going through bad form and can come back hard, the 2019 WC should be his last one though where he should look to prepare himself in the same way the SA's did in 2015 (Steyn, AB, Morkel, Duminy) where the tournament could be his last; someone like Malik on the other hand did the same thing with the 2017 CT and won it in the end. Dhoni can still play well for India but his finishing skills are long gone and Pandya should look to thrive on that niche, He needs to bat well up the order and never anywhere near the middle-lower order otherwise that can ruin India's plans.
Yuvraj to me looks like he has two moods: one where he looks completely lost at the crease like a baby giraffe and the other mood where he'll annihilate and man-handle any bowling attack, trouble is that he ain't consistent enough and he's not quick in the field anymore. Kohli's bowling choices for the starting XI is very poor, he needs to focus on building a good bowling attack first and then look to attack the opposition.