Additional feedback now that I've experimented more with melee:
-Energy Saber is my favourite weapon so far. Damages on activation and on swing, and can be comboed several times.
-Hydraulic Fist feels underwhelming, but with the low cost, it makes sense. Also, dual-wielding them along with kicking gives infinite combos!
-Pilebunker is chonky but the slow reload relegates it to a secondary weapon in my mind, not something I'd be comfortable using as a primary.
I really like that the ammo limits effectively act as a combo meter on the saber and fist, and the pilebunker explosion was bigger than I expected going into using it. If it didn't have the blast radius it has, I'd probably find the pilebunker to be underwhelming, but as it stands, it feels really solid.
The only thing I wish I had was the ammo/combo count being listed in the stats page for the weapons, because right now, there's nothing showing how many attacks you get before reloading. It's easy enough to check, of course, but would help to have that information displayed in advance.
And for a final note: It's a really tough choice for me between using a shield backpack and a booster backpack when running a pure melee build. Aerial enemies are tricky to chase down, and the extra mobility helps a lot with that, but the extra survivability that energy shields provide is really beneficial (although building around nanites and other healing options can compensate for that).