I vastly underestimated Tempest Barrage's damage potential, for some reason I incorrectly assumed the game surely wouldn't let you overlap the ability multiple times in one spot. With it's augment, fast cast time and cheap cost, this thing is deceptively good at killing. It does tend to stagger tougher enemies out of it's range, but anything other than heavies and eximuses gets shredded by the corroding/viral rain.

Plunder + the new passive is insane.
That's the tl;dr version, at east. Tempest Barrage is absolutely worthless for it's damage, nothing changed there, but it's absolutely amazing at applying tons of Corrosive and (with the augument) Viral procs to everything in an area. Todal Surge is still very much worthless, it's too fast to reliably control and I found myself crashing into walls all the time and just never bothering to waste 50 energy on it. It does grab enemies very well now, though! Here comes the star of the show, Plunder! This ability is crazy good, but ONLY because of Hydroid's new passive. The armor buff was enough to make me able to survive rather comfortable with this janky no forma build I slapped together for testing on Steel Path Taveuni, Kuva Fortress with the exception of Slash procs forcing me to heal through them with my Operator. The Corrosive damage buff is straight up insane on anything with decent status chance. I brought my Incarnon Torid and proceeded to melt everything, including the Acolyte like it was a lvl 20 mission. Tentacle Swarm is a lot more useful now, but I still only used it once for testing purposes. It's an OK CC, but it still makes it hard to shoot at enemies and I would rather have Larva in it's place instead (or other grouping ability).
Overall Hydroid seems really good now, he's a classic weapon's platform frame, with tools to help him survive and buff his weapon damage vastly! Will forma him when I have some time to play during weekend and try him out on a tougher Steel Path mission, like a 20min Circulus run to stress test him some more.

Loki is actually the warframe I started the game with! I had no idea how to use him properly at the start, but once I figured him out he was a powerhouse! Radial Disarm was what allowed me and my friend to go well beyond what out gear should allow us to handle in Tier 3 Void Keys! It's funny how far the mighty has fallen, with Loki nowadays being relegated to Switch Teleporting moving objectives to get them to their destination faster as his only job.
Invisibility and Radial Disarm are still really good abilities, just that other frames can do both things better (cough Octavia cough). Switch Teleport has it's niche gimmick but outside of it, it's completely useless. And Decoy really ought to not have limited hitpoints, it's a holdover from ye old days that should have been removed long ago.

Rhino! The frame that has aged like fine wine, the true rock that stands the test of time unwavered (sorry Atlas). A perfect first non starter frame for new players to obtain, giving them both the durability to withstand any challenge and the damage boost to take it down. And he never falls off like some other frames, his Iron Skin isn't the best survivability skill, but its far from the worst, and Roar (even if it is subsumable) remains the best party friendly damage buff in the game. Stomp is a decent crowd control, especially early game. Charge is his only bad ability, but even that one can be salvaged with it's augment, or just subsumed over. Fantastic warframe overall, praise be his mighty codpiece!