I played a GL/AR build on all 3 difficulties, one that would be described best as "medium" in relation to your builds.
TBH those are both the most OP weapons in the game, even on dominating the only feats you really need are Concentrated Fire and Full Auto (Str 7 is kind of worth it for the mag cap on GLs, more than Pack rathound for carry weight) and on the GL side Tricky Trajectory. With the temporal haste spell, drugs and blitz if you go for AGI 10, although 6 or 7 for either sprint or hit & run is more than enough - your first 3-4 grenades with enough preplanning will decide most battles in your favor. The only difficulty for me was crawlers but I solved it by adding 150 effective MT skill, the fire aura spell keeps them away. All in all the build is extremely flexible and even in the most suboptimal configuration will give you an easy time with a decent sense of tactics and positioning. On any map the best terrain is a funnel for enemies to approach you with the width of your GL blast, thats pretty much it.
