It'd be cool to get more synergies on older characters, bring in more variety with who you place on your team and maybe make some undesired characters a bit more useful.
I'm only bringing this up now because 4 has always been the highest amount of synergies a champ ever had, until this update came out.

Black Bolt gained a new synergy with Karnak and pushed it to 5 total synergies, with some space for more.
It'd be cool to get some more unique synergies but that might be a bit to much work, but I'd at least like more regular synergies added to older characters.