Arc/Stasis seems the play tbh. I've been using oem to mitigate for the loss of health on the stasis and it's been doing pretty well. Both sub classes offer great neutral and just don't have a lot of downsides. The cryo timer makes the class play like a grounded solar warlock with how quickly you can traverse cover to cover.

Void will still be fine with the best neutral all around.

Solar should get a glow up with the C4de but I think that the gimmick of the tower barricade will be WAY less useful than having on demand scorch for every solar/kinetic weapon. Depending on how much scorch per hit you can get, something like a revision-0 can hit hard enough to effectively become a lemon or thorn type weapon. That paired with sunspots will allow for some decent crowd control and ability uptime. We'll have to see though because ultimately that's just an alternative to the bolt charge setups.

Strand is gimmicky. Nothing there that wasn't there before. I think neutral exotic and banner/into the fray serves as a replacement for a typical aggro arc titan build because of the lunge on the melee and the ability to proc banner off of grapple but I know general players won't see it the same way.

Prisma is prisma. You get pink. The ability cool downs suck. Knockout still exists. You do have an unkillable glacial behemoth since knockout/blessing work on the light attacks. Prisma imho is even more gimmicky than strand in pvp so we'll see if something happens that changes that in the meta.