A lot of older characters really need some buffs, especially the original units. They can be useful in some situations, yet only in about 5-10% of situations. Yax is someone who could use a buff that helps him stay alive longer to heal others, or be immune to certain disables.
Judy could use a buff of delivering True damage to get past Cricket bat creeps, or has her target someone else besides front line creeps.
Nick could use a huge armor buff, as he goes down so incredibly fast to normal damage.
Bogo is good. I mean, he’s probably one of my favorite tanks because he survives. XD