TFT Rek'sai is kinda terrible

She's melee ranged, so she has to be on the front line to do anything, but once her mana bar gets full she becomes untargetable to dash behind the enemy... who promptly target the next guy back on her team and move out of the way. So she ends up diving the backline and briefly knocking up one suboptimal champion, whom she proceeds to do little damage to because she isn't an assassin. How about making her dash end when she's behind the champion she was aiming for, even if that champion has moved? OR Just make her dash knockup more than one champion?