I agree and understand that if you want a succesful round and if you are understaffed, that cell wars is a good tool to limit the reds and tone the amount down. Say yer 2 to 28 as Silly said, understandable.
Constantly having failrounds with rebelling reds is not fun for blue's (and for some reds) and I can understand that. Truly, I can understand as I've been killed many times due to this.
However, after playing for a while and seeing the different sort of matches, dare I say that it mostly relies on which skillset the warden/guards play.
Think about it: is it because the reds are good at rebelling or is it because the blue's don't know how to deal with reds/rebellers, even with crits?
It sadly enough relies on the latter in my opinion. You can be the best rebeller in town or have a group of strong communicating rebellers. But if the blue's are stationed at good positions or know how to deal with reds, then even the best of rebellers and groups of rebellers can have issues.
can't improve without mistakes and challenges
Learn from the positioning, give orders like "crouch walk behind your heavy" to avoid runners, so many tools. It's a learning curve.
Cell wars ain't the answer to solve problems (I always use meatgrinder if the reds are being too much to handle

)
I'm 1000% sure this vote won't pass, but I'll state my opinion that I find cell wars to be a cheap minigame.
Aside from having classes which can EASILY overpower other classes, the LONG spectator times and the 1 per cell order, the true thing I dislike is how it's just a simple way out of a situation without truly trying the alternatives.
If I were to suggest ways to ATLEAST make sure that the classes have a fair chance, I would love to suggest a same health bar plugin (from scouts to heavies having the same health bar).
I know there are complications (kunai spy), but it's a option to think about. I used to be a regular at a JB server which had that option active.
(The other options that server had was having all the classes the same speed and having both reds and blue's crits, but I won't suggest that)
And the suggestion Krook made is, after some thinking, a good one too. Having cell wars only playable with these amount of reds (number can be decided later on).
Anyways, thanks for reading my rant if you made it this far.
(for the ones saying that the minigame is a rare occurance, I respectfully disagree. Sure it's currently pretty rare and I like seeing that. But the matches I've mostly been on (september to november) I've seen it happen almost daily. Maybe 2 to 3 matches a day, so it's not that rare)