Currently lvl 78 Maya. In the wake of the lvl80 upgrade which really opens it up and gives new possibilities, I put some of the questionable skills to test. Especially in the Cataclysm tree, which is inevitable for getting Ruin but also requires you to spend some mediocre points only to get there.
I tested them with no badass ranks/mods/relics etc. to get a better idea. If they’re useless without them, it’s probably not worth spending points on them either with class mods boosting them. Also note this is UVHM at level 78, these skills may be more useful in normal mode, but in normal mode it makes just as little sense spending precious skill points on skills that make it slightly easier to kill the weakest enemies. You need those points for skills that help you with the tough ones.
Cataclysm: has quite a few useless skills, but you MUST have Ruin, so you should always spend 26 points here, no more, no less.
Flicker: pretty useless in UVHM but still not the worst choice. I put 3 points there to get to Ruin.
Immolate: useless against non-flesh enemies, but not bad against flesh enemies. Not a great skill, but in the light of having to spend points in this tree somewhere not a bad choice, went for 5 points there.
Helios: useless. Would be worth 1 point if it staggered enemies like Blight Phoenix, but it doesn’t seem to do any such thing. With 5/5 it managed to reduce larval varkids to half health. A nomad regenerated health faster than Helios damaged him. Just forget it. Not worth a single point.
Backdraft: useless. The melee damage bonus is miniscule, it only works against flesh enemies, and Maya is no melee character anyway. With 5/5 it still took about 10 melee strikes to kill a larval varkid. The fire explosion does so little damage, again just forget it. Not worth wasting a single point.
Blight Phoenix: I’ve called those other skills useless, but that’s nothing compared to this. On 5/5, larval varkids regenerated health faster than this damaged them. The damage output of this is simply nothing. It’s still worth spending one point because it staggers some melee attackers, which is great, but if you do so, look out for barrels around you. Every point after that first one is completely, utterly wasted.
Harmony:
Elated: not so bad, but mainly a multiplayer skill. in SP, barely ok.
Recompense: completely useless.
Sustenance: makes a little difference, but just a little. Health regeneration is very slow even at 5/5 and is destroyed by Sweet Release and especially Life Tap.
Life Tap: this is outstanding. Makes you heal all the time as if you were holding a Moxxi weapon, but with any weapon whatsoever. One of the best skills, the big downside being that it’s so high up the tree you’ll have to spend a lot of points on stuff that’s not very useful in SP.
Motion: it doesn’t have the best capstone skill (that goes to Cataclysm), but aside from that it’s friggin awesome. There’s not one single bad skill here. Aside from Fleet which is ok but situational, everything here’s at least good.
You may argue about Sub-Sequence and Thoughtlock which have pros and cons, but under the right circumstances they’re both very powerful. Accelerate is maybe not great but it’s good.
Aside from these 4, in my opinion it’s generally best to max out everything else. Which is kind of a bummer for Harmony’s Life Tap. I’d love to have Life Tap, but getting there means missing out on too much of the awesomeness in the Motion tree.
Of course this is all subjective to some extent, I’d love to hear your thoughts if you disagree.