I think they should just remove the Xayah indicator when she's not there honestly... it gets annoying. His best partner is probably Lucian; even a mediocre Lucian is better than a base Xayah regardless of the buffs they get with eachother.
I'll take a Lucian over a Xayah most times for that reason.
I'd even consider waiting 'till they've locked in their AD before hovering Rakan.
Idk if the duo would boost or nerf the WR tbh. Duos are such a cointoss...
Maybe the increased E range is buffering the duos' mess ups a bit?