>Four knights of Gwyn as boss or at least without Ornstein which can be used for Ornstein and Smough ultra
Go all out with fanservice and reused asset from

JUST GO ALL IN FAN SERVICE:
>Artorias, Ciaran and Gough boss (kino service)
>Ornstein and Smough (this duo is thematically the best duo they've ever done also their soundtrack is too good to not recycle them, no idea how to balance them up for Nightreign thougg, maybe make Silver Knights (from DS3) come through the entire fight and make the fight a bit longer than usual aka make them tanky af)
>Darklurker but he splits in 5, first in 2 and both of the 2s split in 2 as well
>Manus + just Manus, this motherfucker doesn't need any help he's brutal as he is

Also a nice idea as an alternative of Day 1/ 2 bosses would be if instead of just 1-2-3 bosses it could be a lot of trash and elite enemies so aoe classes like Guardian can have their spotlight and Revenant passive can be useful.

>TL:DR sum fan service

And now that we got a few leaks of the phase 3 fights i hope they also just go all out and make the harder versions of the Nightlords spawn some Adds too for Revenant passive to do something there and shake things up, maybe not all bosses but Heolstor summoning a random lesser version of a Nightlord would be pretty kino or Adel summoning some small drakes i mean he's a BARON of night how come he doesn't have goons...
>b-buh solo mode
Just don't spawn any adds in solo mode duh.

>TL:DR sprinkle sum adds in the night lords fights but not when you're solo