Lychguard themselves aren't that bad - a little overcosted, maybe, but their actual stats are about right. The problem is they lack a cheap, reliable delivery system. I've seen them used reasonably effectively as a counter-assault unit lurking amidst a large, advancing phalanx of infantry, but it's very difficult to push out aggressively with them. That might be by design, in which case a greater points cut would be appropriate.
Praetorians, on the other hand, have the exact opposite problem. They're fast, thanks to their Jump Packs, but have very little hitting power. This is a relatively easy fix, though - just cut their points and bump their melee stats up so they can deal more damage in CC, and they'd be workable.