Relics are not the hard farm (at least not up to R5). GL13 is.
Instead of stars, look at gear level - I always thought it could have been fun to start adding relics at a lower gear tier though. Perhaps R1 available at GL8, R2 ar GL9, etc. That would make it possible for players to focus more on toons that they like, rather than what is dictated by the current metas, since a GL9R2 Ugnaught may be able to beat a GL12 Revan (unlikely, but you get the picture).
It would add variety and customization to the game for mid level players, while still maintaining a fairly well defined meta that is mostly available to big spenders that can take any new toons to GL13R7 quickly. It would mean greater options to fall back to your favorite team when a new meta is introduced, at least until everyone has that new team GL-ed and Relic-ed.
As it is now, Relics do not offer any customization - actually the opposite, since it forces you to invest even more into any single character, that may eventually fall out of favor, and you have to start on another.
IMO, There is no reason to add Relics to lower star levels. Even a mid level player has all of their (usefull) roster at 7*, and I think that it is a reasonable requirement and grind for having access to any Relics.
I suspect that suggestion is only around because of GAS. There is no reason to change the game for one irrelevant character, that had a release that everyone knew would work exactly as it did. If you didn't hoard GET, you weren't ready for the event (to produce a useful toon) - it's that simple.