I think Syndra needs a "rework".
Moment she gets chalice, will NEVER run out of mana ever again. Enormous damage potential without a single damage item, on demand stun, and an ultimate which I suspect does more damage than Veigar to a single target.
Perfect candidate for an Ahri/fiddlesticks/cassiopeia rework. Some possible suggestions, remove base damage but add it in as more ratio. Maybe give her a 10% larger mana pool, but increase mana costs by 50%. Or any other 1 step forward, 3 step back.