I only, just now after years of having it installed, got around to playing through Throne of Bhaal with the BP Version of the Ascension Mod. It was not worth the effort.
The default final battle is a slog, there’s no denying that. The Ascension final battle? Even more of a slog. Not only does it double down on the cheap plot-invincibility bullshit… it adds an extra battle. The default has you facing off against the various Elemental Princes interspersed with mini-fights against the Final Boss. The Ascension version has you facing off against a bunch of demon groupings (in place of the elementals) followed by a fight against the five earlier bosses plus Gromnir/Sarevok. When you kill some of them the Final Boss makes their appearance and starts attacking as well.
Now if it just ended there it could definitely be seen as an improvement as the whole ‘repeated end boss fights’ bit in the default is beyond annoying. Unfortunately, once you get the Final Boss down to ‘near death’ they get scripted invincibility and do that whole default “recharging” bit, being instantly restored to full health. They do this twice… same as the default. So not only do you still have to face them repeatedly you have to do it with no rest breaks in-between while also re-defeating those five bosses from earlier. Total bullshit.
What about the ‘improved’ boss battles though? Improved Yaga Shura is dumb. Having to sit around twiddling your thumbs for minutes on end waiting for plot invincibility to slowly wear off is not fun, it’s just a waste of time. Sendai suffers from the same issue; now you have to hack at her for 5+ minutes to finally whittle down her ludicrous plot-granted health buffer while she teleports between three locations. How is this fun or ‘tactical’? It’s just pointless busywork. The Gromnir, Abazigal, & Illasera fights seemed pretty much the same as I remembered them (perhaps they were overridden by SCSII?) while the Balthazar sequence was skipped due to talking him out of the fight (huge improvement).
So yeah, one of two things is going to happen now:
1) Uninstall Ascension and forget it exists.
2) Edit the script so that the first ‘death’ kills the final boss, skipping the recharging bit.