I like your idea. I actually enjoy what ESO has with the zone scaling. Blizzard just did something similar with WoW. Makes the leveling better as you don’t outlevel everything. But for ease of doing, instanced would be great.
Personally, I can’t hang out in Kaidan - I know the rewards are better, but I spent way to much time there in TSW. I tend to bop around the map depending on my mood and often go do missions I haven’t done in eons. I also do have two alts - one sat in CoTSG for five months until the agent system. The other’s still in Sol Isles lvl 40 as he’s doing everything, so no challenge there.