Slave Driver Mana Guardian. Ridiculous power/investment. I expect summoners overall and slave drivers in particular to get nerfed. My dislikes were typical summoner shit(I hate having minions kill for you), and that delay waiting for ES recharge to kick in. Uber Elder was a shitshow too, but I imagine part of that was user error. I wasn't timing my recalls very well.
Zombie Mana Guardian. An attempt to solve ES recharge with ES leech. I didn't put much time into this character as the clear was unsatisfactory. Minions already feel like dragging a pack of ADHD dogs through a map, zombies are the worst of the bunch.
Static Strike Elementalist and Gladiator. First one was Mathil's build. It was ok, dropped it eventually as Static Strike's nature is at odds with itself. It will kill packs before you can swing at them, guaranteeing you will run into a pack without the buff up. Tried Gladiator version as challenger charges and bleed pops seemed promising for ridiculous clear speeds. And it was, well into the late 80s I was getting over 500M XP/hour. Dropped it because it was TOO fast, Static Strike's range kinda sucks(felt worse than BV) and there was still the aforementioned buff refresh issue.
Elusive Abuse Assassin. This is basically a juiced up HoI-chaining build with some of the new Elusive tools. Definitely the most fun to map with. Bosses, not so much. I tried BV and having to run up and hug packs to get a HoI chain was mildly annoying. Also, melee positioning when you have +250% movement speed is actually a major downside. I tried WOrb too and it solved those problems. I would recommend both versions of the build except for Uber Elder farming(WOrb is quite dumb here) and deep Delving. The build relies on avoidance, so challenging content can lead to one-shots. This build is REALLY fun for theorycrafting.
Voidfletcher Ice Shot Raider. Didn't play it much, felt it was pretty similar to the above but worse at clearing and better at boss dps.
Mathil's Magma Orb/Ice Spear build. Gave this another try this league, not sure why, came to the same conclusion. Inconsistency in triggering is really annoying. I hope they change crit calculations for 4.0 as basically any build that wants to do CoC has use cyclone and this build does not function with cyclone.
HoWA Wild Strike CI Trickster. Clear was great, blight was unfriendly to it in higher tier maps, dropped it because of that.
Cold Cobra Lash CI Deadeye. Clear was decent to pretty good. I think relying on one "model" of damage can lead to issues. By that, I mean just having a bunch of chaining projectiles without secondary explosions. Since projectiles from one attack cannot hit the same mob more than once, you either have to one-shot the pack or fire into it multiple times. Dropped it because of that and my single target felt flacid despite what PoB was telling me.
Also rolled a Storm Brand Mana Guardian but meh, nothing changed with that build.