Alteration's actually pretty solid once you commit to it, but yeah, the early game feels thin. You're hitting the wall where Mage Armor is good but not game-changing, and Paralyze costs like 700 magicka to cast once.
The thing is, you need to push further. There's a perk line deeper in the tree that makes your Alteration spells way cheaper to cast - that's the turning point. Once that's active, stuff like Paralyze and Transmute become actually spammable, and suddenly you've got crowd control that Destruction can't touch. Paralyzed enemies just drop, and you control the entire fight without burning through your magicka pool in two casts.
Also, the damage reduction scaling from Mage Armor gets stupid good if you level it alongside the perks that boost it. By like level 40-50 Alteration, you can stack enough damage reduction that you're basically a tank in robes. Sounds weird but it actually works - I've done full Alteration playthroughs on Requiem (PC obviously) where I barely needed Restoration.
The utility stuff you're dismissing - Waterbreathing, Muffle - yeah, those suck as daily drivers. But Transmute Ore is genuinely useful for smithing profit, and there's perks that make your transmutation spells better. Paralyze + Mayhem effects = you're not even fighting anymore, enemies are just killing each other while you stand there.
Real talk though: if you hate it by level 30, pivot to Conjuration. No shame. Alteration's a slow burn and needs investment to feel good, whereas summoning is fun from the start.