No retcon can ever be good, especially not a half-assed one.
You know what could have been changed in the old lore to have it make sense?
- Making some of the characters dead and being summoned as dead.
- Saying that at a point in the League's history a rule was introduced making the pick&ban phase canon, aka every confrontation between factions could chose any champion from any faction.
- Having "artificial" champions. As such, Aatrox, Bard, Tahm and the Kindred could have been created based on the popular beliefs regarding them, and then "magically" appear to be partially infused with the spirit's consciousness.
That's it. Summoners were a great thing, false deaths were a great thing to explain respawns, minions were nice, RAMMUS MADE SENSE, SKARNER MISSED HIS KIND. What the living fuck was this idea of flushing all of this down the toilet?