The interaction and empathy skills are must haves for me! I kinda expected that though. I really liked the piloting and intrusion skills and felt like I used them in more activities than I thought I would at first! I barely ever used the terrain skill I think. Also I second bluepanda's comment earlier about missing how LLTQ had learning tree boosts, I feel like those rewarded you for specializing and made it way easier to max out a tree.