I think we would also need to do some much needed updates to low tier existing sets, specifically:
3) Dwarven Defender
Here's a link to k3d's old post on beefing up the Paladin/BG sets:https://www.realmsoftrinity.com/Forum/viewtopic.php?f=4&t=5259&p=39862
For the base classes, only Scouts lack a class-specific set. Not sure what a good new set would be without being very niche, as there are a lot of less than useful PrCs. Maybe a Dragon Disciple set?