Transmuted Spell is very weak compared to the Scribes equivalent. It eats a precious metamagic slot, chews through your Sorcery points, can't transmute spells of 6 damage types, and you can't even use another metamagic at the same time, giving up one of the few advantages a Sorcerer might have otherwise had. If you want to stay 'on-theme', it's also asking a lot of your limited spells known space to have a decent assortment of storm spells (for when you don't have SP to spare) and non-storm spells (for when you do).

By contrast the Scribes Wizard can casually bypass the resistance of every creature in the game, with a far wider array of spell shapes and such, and more casting resources (since they don't blow their Arcane Recovery in order to fuel their type changes).

The Draconic Sorcerer is also looking at a far worse spell list -- not only because a lot of important blaster role spells aren't even on it (like all the summoning and minionmancy spells, action economy amps, etc), but also just because you have so few known that you're going to have a lot of gaps even among the things that are on your list.

And then there's Manifest Mind, which gives you a considerable advantage in terms of senses and positioning, and allows you to use some of the storm-themed spells in important new ways (such as examples given in posts above).