Fiora is I think by far the worst, to the point that I think she might be intentionally bad to keep early nobels in check. She is super squishy, and her ult seldom does much of value.
Elise is I think actually fairly decent in a shapeshifter build, especially if she is given a mana item of some sort. Literally just a plain unupgraded tear makes her much more useful. I do think her spiders should be made better units at the expense of the player damage aspect though. As she is right now she can lead to some really nasty early losses from being made to fight a 2 star elise repeatedly.
Lissandra is a vital part of my emergency backup builds of elementalist sorcerer and elementalist glacial, which I go for if I find myself in midgame with barely any 2 stars or synergies of any kind. The fact that the elementalist synergy has the same strength regardless of the level of the units involved make it, and by extension her, really valuable for surviving midgame if things get off to a rough start.