It amazes me that people don't think scout is the most OP class. Free intuition is huge.
Well, it's hardly free as you still have to spend the traits, you just don't need EE2 first. And depending on the build and challenge, I'd often prefer spending the traits elsewhere.
Yes, Int is good but the better I'm getting, the less I feel I need it.
Whereas I don't think I've ever played technician without getting WK.
The stair sense is ok, but in the challenges where it'd really be useful, it's not available. Additional speed is nice, but I still prefer the additional health and powerup duration of the marine or the tracking maps of the technician.
And the scout master traits aren't really that tempting unlike Vampyre, Ammochain or Scavenger.
But I'm not an expert player so take this with a grain of salt...