It is puzzling why it takes them to implement features so long. Just as if they had a good idea (warfronts/islands) and cut them in the middle which makes them just boring and halfassed.
But maybe this is it? They are trying to be unique on every aspect while in reality... If they did reuse old assets maybe we could have gotten more polished features.
Because honestly... I'd rather have old models, old buildings old stuff WITH fun mechanics, than new shiny looks with shit replayability.
Like for example with my idea of scenario
Reusing Slices of old world as maps (there are many fascinating places that are basically begging to be reused)
8 buttons
3 to command sidekicks
5 special abilities that rotate each week (or even each run) LIKE:
1. Glacial Ray from Jaina:
2. Burning Rush from Soulbound Goliath waycrest mannor (when you move them to fire):
https://www.wowhead.com/spell=260547/burning-brush
3. Transfusion from priestess Alun'za (Atal Dazar) rays that suck enemies HP. - A bit more defensive cooldown.
4. Sweeping Scythe from argus the unmaker - Frontal cleave with nice visuals.
5. Some defensive boss ability (can't really take one on the top of my head)
I would be so thrilled to use boss abilities in this scenario.
TL;DR reusing assets to cut development time BUT providing a polished result is imo much better than trying to implement something new each time and delivering half-assed solution.