Yes, we want every ability from every expansion to remain. That has been the main complaint about borrowed power since it was tested in WoD with the "Draenor perks" and introduced for real in Legion with the Artifacts and Legiondaries.
Blizzard introduces a new system that's shit in the beginning of a new expansion, keeps on making small changes and finetuning it until it's a decent system that actually works at the end of the expansion, then scraps it again when it finally works, only to release some broken shit system at the beginning of the next expansion, and the cycle continues...
Cata and MoP was the objectively best expansions for classdesign (yes, if you disagree with this, your opinion is wrong). Why? Because we had fully working modern classes WITHOUT ANY EXTERNAL BUFFS OR ABILITIES. Cata and MoP classes were designed to have their full toolkit once you hit maxlevel.
That's a massive contrast to the Legion/BFA classes that were absolutely broken and simply didn't function properly without the borrowed power from their respective expansion. SL reintroduced a bit of pruned stuff and made the base classes a bit stronger, but they are still nowhere close to as complete as they were in Cata/MoP.
In a perfect world, all the stuff we got from the borrowed powers in WoD/Legion/BFA/SL should have been added to the base classes instead. Redesigns/changes between expansions will naturally prevent ability bloat from becoming a problem. MoP was the height of ability bloat, and it was nowhere close to being a problem then.
Also, stop taking stuff that used to be baseline in previous expansions, and reintroducing it as a fucking talent in the new expansion. This has been such a huge problem that it wouldn't surprise me if Blizzard took Fireball away from Fire Mages and made it a talent instead...
Come up with an idea for something new and cool for the next expansion, but instead of adding it as borrowed power, they should... wait for it, here comes the revolutionary idea... add it to the base classes instead!Any one can whine about stuff, you have to offer a better alternative.
Which is exactly what we have been asking for ever since it was announced that the cool Draenor perks would not be baked into the base classes at the end of WoD.