I've been considering training up a Klingon boff for this kind of ground combat. Is it worth training up abilities like lunge and leg sweep, or would it be best just to give him a Bat'leth and some physical augmentation armor and let him hack things to death?

if your setting him to melee, legsweep, lunge, target optics and motion thingy would be the ones I'd look to give him

Not to rain on your parade here but unless a patch has been applied, BOs will simply stand around doing nothing if you ask them to use a Bat'leth or martial arts. I wanted a Bat'leth wielding Klingon myself but he just spammed his special abilites without ever swinging his weapon.

I think this might actually be a new conditional bug you're seeing...

Experienced it myself last night... and bugged it... but after an abort ->> restart, they went back to actually fighting with all skills (including melee)...

Don't quote me on that...I'm just saying that was my experience...

I equipped 2 Tac, 1 Eng and 1 Sci BOFFs with bat'leths. The Tacs ran in and chopped away. Eng and Sci just stood at ranged and used their special powers like heals. When I swapped the Tac back to ranged weapons, they would run into melee range and then begin shooting. Very weird. Clearly a confusion about when to apply which AI combat pattern. I will try the above mentioned abort and restart.