tl;dr: full houses suck because they arent specialized, make jokers that allow full house to help with setting up for your main hand
Generally speaking, I think Full House (FH) is the hand that gets the shortest end of the stick in most runs. From what I've observed, the problem with the hand is that with all the Joker synergies it has going for it- you're better off just leaning into either any #oaK for scoring or Two Pairs for consistency.
However, I also don't like the idea of FH-exclusive scoring Jokers to enable it, since the plethora of Pair/Three of a Kind/Two Pair Jokers already fills that role.
To solve this problem, my proposed idea to help give FH a place in more runs is to add utility Jokers that activate from playing a FH. I think as is, FH is the best hand you can pivot from into your main scoring hands, so emphasis on this aspect could very well be the best way to help it. Here are some half-baked ideas I've thought of:
Architect (Rare, 8$):
Create 2 Tarot Cards when a Full House is played.
The Builder (Uncommon, 6$):
When a Full House is played, add a card with the same rank as the more abundant rank in your played hand. (I don't know how else to phrase it or how vanilla this is, but basically if you play 9-9-8-8-8 then an 8 is added to the deck)
Cement Mixer (Uncommon, 5$):
When a Full House is played, turn all played cards into Stone.
House Market (Common, 5$):
When a Full House is played, gain money equal to the highest rank played in your hand.
There are definitely more ideas out there to fix the issue, but I would really love to see Full Houses be made more viable in the future.