Lowest damage potential in the game. He needs damage buffing or armour removal
Tentacles move enemies out of range, necessitating radial weapons (and making most of them significantly worse due to the length of the tentacles)
THE CAST TIMES
Also a mild nuisance that Barrage essentially doesn't scale off range. The knockdown radius does but big whoop, that's not how you use it anyway.
I love Hydroid, and I have a hot take that he's really good for when you get him due to having what you need to clear the starchart in a really fun way, but by god the scaling on this poor frame is atrociously bad.
Anyway, some hopes:
Passive is some kind of damage buff or a loot buff.
Undertow and Tidal Surge are merged. New ability is a damage vulnerability or an armour strip. (I don't see them buffing Barrage given they completely passed over Corrosive Barrage previously, maybe for Helminth reasons.)
NO MORE CAST TIMES
Tentacles have damage transference a la Tornadoes, or at least don't lift enemies up in the air where you can't hit them. Suction effect so enemies actually get caught in them.
Tentacles scale off range or power strength, or at least spawn intelligently according to the navmesh so you don't get random wasted tentacles doing SFA.
At the very, very least, I would like his 4 to just hold enemies still and rooted to the ground, rather than flailing them around. It's as annoying as swinging enemies in a Khora dome, and there's no easy solution like the Khora actually using her whip. We're away from the aoe Bramma/Zarr spam meta now, we're in the precise headshot Incarnon meta :^)
I feel like his 1, 2, 3 all need some sort of extensive rework and possibly larger changes. Undertow is a cool idea but just... lacking in any oomph. Tempest Barrage's cast time is too long. Tidal Surge just lacks oomph again. Any stronger and interesting synergy between the abilities would be better than what he's currently got
Or just do it like the Zephyr way. Shoot the tentacles and redistribute the damage. Though I'm not sure if that would be better or annoying since it may unintentionally block weapons fire if there are a lot of tentacles.
It would be great if shooting/hitting the tentacles transfers the damage to the trapped enemy, but if it increases the damage in any way it will basically be a copy of Zephyr's tornadoes so I don't know if DE would go that route. But yeah - I'd honestly just rather the tentacles hold things still than flop them about all over the place, it's a lot of visual clutter
Tempest Barrage - Let it fully armor strip and bake the augment into the ability.
Tidal Surge - Enemies hit by Tidal Surge are grouped similar to Mach Crash.
Undertow - Replace it with something Siren themed. Lures enemies towads a Siren, enemies within n-meters take extra damage. (I think I remember them saying something about replacing one of his abilities).
Tentacles - More Tentacles Less flailing around, and maybe group captures enemies into the Kraken's beak/mouth instead of flailing, or have damage done to a tentacle transfered to the enemy. I also remember them just ignoring enemies occasionally, would be nice if they were more grabby.
I'm of the opinion that reworking warframes generally is not worth the effort but there are exceptions, hydroid being one of them. In most cases I think adding a new warframe is better than a rework in case there are enough people that liked the old abilities. With that in mind I think his abilities need to be improved and made more fun instead of scraped.
reduce cast time and remove charging. He's just too slow.
replace puddle with a water form that starts at 100% damage reduction and reduces to 0% damage reduction towards the end of the ability as he dries out and as it negates damage.
increase damage for his abilities by the number of tentacles spawned. Damage of abilities increases by 10% per tentacle active.
tentacles don't grab enemies but attack them and stun them. Tentacles grab corpses and throw them at other enemies.
killing an enemy has a chance of spawning a tentacle in addition to ground slams. Raise the maximum number of tentacles from the passive to 5.
enemies hit by tentacles take 10% more damage from all sources every time they are hit.
Maybe his Tidal Surge can be a maintained ability that balances on duration and efficiency? His water body can just absorb damage/let bullets and melee attacks pass right through, while also giving him some fast mobility. Let him absorb enemies as a water blob and kill them, like his Undertow, and more enemies killed = longer he can maintain the form OR more damage he can dish out as a killer water blob.