How would you incentivize playing this spellcaster vs a class that doesn't kill itself to use its class features?
Note that ‘Push your Luck’ games are popular so I can see people enjoying that sort of gameplay, especially if there was way to mitigate the risk through various tactics (like hiding behind cover to begin casting so enemies can try to disrupt you).
But other things would be to make Cantrips more fun, giving them variety of effects beyond boring damage.
Another is that there would no longer be spell slot to track: You can cast Fireball all day if you’re ready to take the heat yourself.
Furthermore, the risk would be relegated to spells that can cause harm to others, or maybe to types of divinations that can ‘cheat’ the game.
I would move a LOT of non-combat utility magic to an out of combat ritual system where failure to perform them properly would just cost some time and some components. Components that I would probably try to make more engaging. I could see one of those ritual basically be ‘replace a skill check with your Arcana check for an hour’ but each skill would require a specific plant or something.
The idea would be to make spellcasting more engaging and not a simple point and click exercise where you just use the best option when you have it and use the second best when the best is no longer available. And no matter how many fights you’ve gone through, you always have the option to pull out ‘The Big Gun’ when things turn sour… but your allies might just have to carry your unconscious body out of the fire once you pull that trigger, ya know, even if you succeed. (this would give high STR a solid function

in a way).
I’d probably get rid of ‘preparing’ spells too. You learn a Spell, you know how to cast it. Any spellcaster could find books with extra spell for them to learn as treasure.
Or a % table, kind of like the Wild Magic table, of all sorts of things that can go wrong. Could be a ton of fun. Maybe that's how the Sorcerer class could be really different from the Wizard. No spell slots, just risk.
Oh yeah, fix the biggest issue with the Wild Magic sorcerer: You get to pick when to roll on the table by trading that risk for an advantage.