It’s too long to be honest in it’s current form.
It doesn’t help that every year there’s a couple of teams at least for some reason that isn’t at the races for that season, whether that is due to them playing catchup after a poor mega auction or injury to a key component of the lineup. Sometimes it’s multiple players going on a bad run of form. Once you’re down a few games, it becomes increasingly difficult to get to a number four spot, doubly so when it isn’t as valuable as in a traditional format where you could still make the final with one good semi-final (not that I’m condoning it since finishing top two should get you an extra benefit). Given how the IPL isn’t taken as seriously from a competitive perspective either by many players, it’s not a coincidence that morale drops and the bottom teams just go through the motions after a point.
This is where I feel the IPL could benefit from adding an extra knockout place like BBL did briefly. It would add more incentives for even the bottom teams to keep faith in their campaigns being resurrected after a couple of wins and it would bring it back to 50% of the standings contributing to a knockout place. I doubt bottom teams would care about the extra game when the race to fifth is slightly easier.
The impact sub rule has also inadvertently caused totals to go up (I haven’t done the math yet but it wouldn’t surprise me either way) it feels like. Teams are using it to extend their batting depth more often than not, resulting in a 12v12. The extra bouncer rule was supposed to help bowlers but it’s also caused an inadvertent change that’s currently plaguing test cricket where bowlers just keep bowling short balls at you since the current limit for wide balls is quite beneficial to bowlers than batters and umpires tend to stay on the side of the bowler more than the batter. Some players pick up on it and just go ham, resulting in a flurry of boundaries or struggle to deal with it since playing bouncers properly is not easy in the first place, especially with modern helmets and coaching techniques.
I’m not sure how I would change the impact sub rule but in its current form it’s really boring since it is the same or similar set of players being subbed out or in. Maybe teams need to start using it more creatively… or maybe you’re only allowed to sub someone out if they’ve already bowled at least three overs by the end of the tenth over or lost their wicket/is currently batting? It could encourage more creative bowler role usage for bowlers while for batters aggressive batting is a reward for powerplay specialists with the risk of it falling apart if you lose too many wickets upfront? You could still have an anchor walk in to steady the innings or retire out an accumulator who has a tendency to get worse as they bat through the middle overs.