Because a lot of the powers would have to be disabled to account for various things last I checked. (ie stuff like toxic or homing projectiles would have to be disabled because of accidental spawnkilling)
Rolling for random debuffs with a minute chance of the probably not very helpful thing isn't very fun afaik. And assuming you are not being facetious, it doesn't so much balance them out as it does double down on the issue.
Personally I dislike the rng based nature of random crits and find them counterproductive to most engagements and irritating to many players. Surf certainly isn't the most serious epik gamer environment, but dropping random crits from the gameplay there does very little for 99% of what goes on there but make people who dislike them happier. Unless you really rely on them for killing those bhoppping mach 10 people it shouldn't even be noticeable were they removed as per literally every other place where they were turned off. Sure it is less random but in a more enjoyable way, surf is already super chaotic and disorganized but that charm is harder to enjoy when you are being instagibbed by the guy you just brought to 2 hp with a pile of sync'd up rockets.
As for the people who have said that they are helpful for breaking jail camps, I'd say you see more success on that front from cleaning out sniper boxes and forcing the other team to take cover/deal with you or bhopping around from the jail teleports as a distraction for your team (fast man make shoot, must chase). Those both are far more common and consistent ways to keep the camps in check that I would see used (and personally did) to great effect in that particular matter. Random crits are inherently unreliable and are probably going to favor the camping team because of the mechanics behind crit frequency, and if you are bad you will just end up camped again so they really don't even help much in the long run.