Balanced ascendance would be cool.
Ideally, figures for the most commonly and least commonly used 5s would be used to make 2 pools, 1 pool of common 5 star recruits that many players could work towards ascending (e.g. blue Ty and Commander Mirabelle), and 1 pool of uncommon (useless) 5s that could redeem those characters (e.g. Gator, Commander Glenn, yellow Josh)
Another possible solution is reworks, or passes, which is a term the SWGOH devs use to mean re-visitng a group of characters that have become outdated, weak, and underused. They rework, or modify, the characters to add abilities and tactics that are typically unique to that group, and that can be used to compete with one or more of the commonly used groups in the current meta.
As an example, check out the Nightsisters in SWGOH. They used to be completely useless, but after a rework and a new character added, a new debuff which bypasses health and is difficult to cure is added to all Nightsister attacks, and revives are much easier to trigger and more common. This expands the meta, making it a more diverse and interesting game.
Could really use more interesting, diverse gameplay here.