Lissandra's passive is awful

Yes she has a free spell every 18 seconds but the passive is rendered useless because of her Q's obnoxious cost of 85 mana at lvl 1. One of the lowest base damages, low scaling, low range, long cooldowns and high manacost.. traded for great CC and average midgame? What's the idea of having a mana passive when her manacosts (at lower levels) are unusually high anyway. Additionally lategame with all the items mana becomes trivial so she virtually has no passive at that point either. Her solokill potential is already very low in all lanes and now with the juggernauts she has no place in the top anymore. Try to lane against a resourceless garen who just afk pushes for 20 minutes while Lissandra has to b every 3 minutes before she gets a few items. She is a good champion and I can pull of alot with her but it's really frustrating to poke your opponent 15 minutes (yes im overstating but you see the point) and when going all-in you run out of mana before even using the ult while a veigar/leblanc/brand/syndra does 70% of my hp with one rotation. Im fine with her having low damage and range but she either needs a new passive or have her Q manacost reduced early.

Another thing is that I used to build DFG on her very often to compensate her lower damge but after it got removed what did she get in return like Ahri and Annie did? Nothing.