Dhoni is still a very capable player. We all already saw how well he has played in this IPL season. His hands are still the fastest for any wicketkeeper in the world in my opinion. He can obviously play one more if he wishes. Actually, I will say that as long as he can contribute to the team well and is not a burden on the team he can play. So, I don't think it is a problem if he decides to play one more season in the IPL. As long as he performs it is going to be entertaining.
CSK winning IPL 2023 under Mahi captaincy says all about his performance. Mahi is almost 42 years old and his fitness clearly says that he is fit for coming IPL. In last IPL, CSK tried Jadega as captain and that test failed miserably, as CSK won only 4 matches and finished 9th on points table. But CSK must try to look for replacement of Mahi in coming years. Its better to find and groom new captain under Dhoni leadership for long term benefits of CSK.
Trust me they are never going to find a true replacement for MS Dhoni. They might find someone who is a good captain but as I have been saying for a long time, MS Dhoni was the best captain for India and CSK. I actually think that he was the best captain ever in cricket. To me, there will be a debate between MS Dhoni and Mashrafe bin Mortaza because these two achieved unbelievable things with very limited resources.
Anyway, I also think that CSK should look for a player to potentially replace Dhoni. Otherwise, they are going to face a lot of problems in the upcoming years.