Here's how I would set up the base Admin levels: (not that your admin power system is bad or that you have to listen to me)
Low-level Admin: Mute,Gag
Basically the person who has to shut someone/everyone up
Mid-Level Admin: The above plus kick,slay
The guy who gives the initial warning and/or a boot up the player's ***
Full Admin: The above plus ban/unban
The guy who deals with all the bans.
The low level would probably just be a glorified regular. There's no point to mutes and gags in administrating a server. Admins' main stuff is to kick and ban according to the rules, and if such a low-level variant of admin was introduced, it would be given out on a whim and cause even more stupidity.
Give someone JUST kick and slay? Protip: People who get kicked for racism or whatever rejoin and spam it again. It's pointless to not ban for dodging, because they just come back on and rage harder than before, and it would just keep that "partial admin" or whatever the hell he's called a headache of constantly having to kick some guy like that.
And being unable to ban would make the majority of the admins useless. I pop on past midnight if I get messaged about some guy with a speedhack or whatever else (within 10 minutes of it happening, since SMAC usually gets it after a while). I suppose it'd be so much more helpful to just mute and gag him while he hacks. Or, I could just keep slaying him and get an earful about that after, or kick him so he can keep rejoining.