I believe the way to make her relevant is to buff Q and E to actually get better with levels, especially Q which barely changes at all.
How about greater and greater armor shred on E per level?
How about a triple attack at level 5 Q?
Level scaling armor shred on her E would make leveling her E more enticing though i feel like minions shouldn't block it, if you compare her to other champs it would be that much stronger, just make hiting the champ easier when they are in minion clumps and if you are fighting in a minion clump it would still hit the champ.
one thing that would make her ult's leap more frequent is to give her a unique item like victor and Rengar but it gives like AD and/or attack speed but the main focus would be doubling the rage gain per second.
the item would be maybe a claw or tooth from the dragon that killed her father, the item would tie in with her lore and would make her more interesting