It depends why you want the gm,
If I was making scripts for the server, for a start I'd want to test them properly on the server in question, not add in poor untested scripts that will without a doubt be abused to hell when a bugs found.
People who actually play mir and want to be a GM to be better than everybody else will no doubt get bored, as there's no challenge. I dont play mir...
It's all about trust, if you want good npc's then you want a gm to write them you could trust or write them yourself. Somebody could always write some very abusable scripts, which I doubt you might spot.
Thought your doing the right thing, the less gms in general the better.