Is it certain that to create a new pool would spread the players too much ? I mean I am sure it can be proven with a mathematical calculation if it’s feasible or not.
But in fact it’s a useless interrogation, as if players are waiting too much in one of the pools (5-minute, 3+2 and 3-minute), then they can click on another one of the three that would be available! So I don’t think it’s an issue to create a new pool, people won’t wait longer than if there were only 2 blitz pools. There would be more diversity in the art of practicing chess blitz! 
Maybe admins are also afraid it would confuse people to see so many ratings categories…But there are already many, so 11 instead of 10 rating categories it’s not a problem either, and people are used to it on the ICC. Personnaly I see it as a strenght to the server rather than a weak point.
So as many people are begging for a pool with increment (3+2), I think ICC staff has to create it and not to remove one other pool!
People would be happy : everything would be for the best in the best of all possible chess worlds, right ?! 
I have to add just one thing: If despite my perfect reasoning(!!) on the subject, the 3+2 pool is not created, then another solution would be to encourage blitz tournaments with increment on the ICC.
