Ascendancy Rework Idea

Introduce unique ascendancy questlines, starting at different points in the campaign that tie into the story more. This would also offer more variety each time you play if you pick different ascendancies, could alleviate campaign fatigue. They should also be optional and not required to get to endgame.
There are 3 trials or difficult challenges that pertain to the mechanics of the ascendancy that should be completable before the final part of the campaign, so your character should feel at their strongest for the final act.
Repurpose the interlude acts as quests only available through ascendancy questlines.

for example, if you play the witch:

Act 2: Infernalist
Act 3: Blood Mage
Act 4: tbd
Act 5: Lich

Endgame offers pinnacle ascension that continues the questline challenges. Abyssal Lich would be an example, but it should be more about evolving your character rather than just having trade offs. You'd also get more points through endgame.
There should also be a "decide your own fate" option where you trade in your ascendancy points/feats and unlock a socketable tree. You unlock ascendant runes through trials/bosses in endgame.

Campaign expansions would also include new ascendancies, making them more exciting.

To go in further on the ascendancies themselves, I think it would be fun if all of them started like the blood mage and have the first free point that grants a unique behavior.
The pinnacle ascendancies and socketable one wouldn't change the free point but everything after it.
When you first interact with the altar it would be cool if a video played explaining the mechanics of the ascendancy like the skill gems.