I had the alts I cared about on one realm, and the alts I knew I wasn’t going to care about (mostly the other faction for uniquely acquired transmogs, buying legion pets, gathering alts & recently-legacy mount runners I use at the start of an expansion, characters I leveled with friends that might come back one day, etc.) would be on a sister realm. Deleting them isn’t ideal, as I do go back and use them every couple years.
Now that they’re merged together, it is kinda annoying to look through, especially with the larger UI.
I personally wouldn’t need a ton of organization, just a “Main” and “Secondary” tab would suffice for me, or an “All” and “Main Focus” tab.
At that rate, I’d mostly be fine with an extended Favorite sections, just need like 10 characters instead of 4.