Leona Rework?
I'm not necessarily asking for a full VGU, but when I play her, she seems... old. :| I like to take her top lane and Bruise with her, and while that has a somewhat limited effectiveness, I feel the same lacking that I do when I support with her as a tank.
Probably the most generic way to put it is that she feels like she needs support... as a support. Without her ADC, she is nothing. Without her, her ADC is nothing. Solo lane, same story with your Jungler. She does pretty good mid game, but the issue is that her early game is pretty bad, especially against juggernauts or Vanguards with pokes, making it really hard to get her to her mid game.