Originally Posted by Gnorman
So, in essence, what would your recommendation be for the engineer? Toning down the power and damage of his inventions? Fewer skill points and a smaller hit die? I'd be more inclined to the latter than the former.
It seems like you want a limited scope, non-magical "mage" type character - which is fine. I would honestly say bite the bullet and move him out of the Skilled Character section and into the mage section, drop skill points to 4 / level and drop The Knack. Leave him as a Trapfinder, and allow the Inventions to compete with - but not outclass - similar level spells in their types of effect.
Up the number of inventions per day up to
2 - -
3 - -
3 1 -
3 2 -
4 2 1
4 3 2
With the +1 invention / day making it 10 spells + Jury rig + Innovation. Some of those spells are basically permanent class features which offset the penalties, whilst he can still just about pull off a solid trapfinder role with 4+ Int.
I'll have a think about where I'd go in the other direction, see what I come out with.