Platinum Kett is going to suck....

I fear the masses of invisible enemies and the glitchy Fiends way, way more than Ascendants.

Have you stared a shark in the face and lived to tell the tale in your oceanic journeys?

Several. Got a bunch of cool GoPro videos too.

I remember 2 banshees at a time and once you killed them 2 more and then possibly 2 more after that. Plus 2 get primes with them on some rounds. Not sue if we will see 6 fiends per round but I would expect 2 to be the bare minimum...

There were waves in ME3 Plat with 2 Banshees and 3 Primes at once, if i remember correctly. That was quite bad in solo I can google the spreadsheet for you if you want.

I think there cant be more Fiends then 2 at once. they simply wouldn't fit physically. There's not enough room on the maps. 

Kett are the only faction that 1) Creates incentive for the players to move ( Ascendants and Fiends actually moving faster than "a walk in the park"-pace), thus getting them out of cover and 2) Having a unique unit which can soak up a lot of attention. The Ascendant is tanky, and needs to be focussed by all players to be brought down in an orderly fashion.

Actually, I like the basic design principles of the Kett, it´s just other factions suck hard compared to them, and that is what makes the Kett standing out.

Yes, Kettplat will be terrible, but a lot of balance patches will hopefully be applied until then, making a lot more playstyles viable. Until then, I´m going to hold my tears of joy.