would guess it was rich if anything. You could always try the spit trick hahaha. I tend to run mine rich all the time as I'm paranoid about overheating and ruining the engine. Really, I feel lucky that it runs right at all somedays and I hate to push my luck.
My revo would bog down real bad like you said(i'd give it full throttle and then it'd start to go). Lean it out a bit and see if that helps.
As far as glow pugs I 'd have a glow plug last me 3 gallons and i'd have a glow plug last me a tank. Its all about how you run and yor tune. Is it wet around your glow plug when you pull it out?