Is there a point to Irelia having mana? It doesn't seem like she loses any.
Literally seen her Q 2 whole waves and only lose a tiny bit of mana. Her highest mana cost ability is her ultimate and it's 100, her second highest is 90 and it's almost a 10 second cooldown late game, Her E only costs 50. Like is there any purpose to someone who has over 1.1k mana using less than 10% of it in a teamfight? I mean I tested it out myself. I can Q whole waves and have my mana pool back up to full in a few seconds. She's probably the only champion I can think of who doesn't have mana issues at all late game that doesn't build a single mana item except Sheen. I mean compensate her with some(not full) mana restoration on her Q if you want, but at least give her some mana costs.
Hell GP only has 3 abilities that cost mana and one of his costs as much as Irelia clearing an entire wave of minions.

, and yeah after that no mana problems to speak of, maybe if you’re wrecking the game and you don’t back till you have 4K gold.