I think the 5E sorcerers metamagic quicken is crazy ...I assume in TT it works (sort of) because you can't long rest willy nilly. But they really should have attached a cost related to spell level (so Larian are being sensible I think from a balance view..odd, they ignore it in so many other places). Clearly someone at WoTC didn't think this class through very well. Still, if it's the official rule, then you're liable to p'off sorcerer afficionados by changing it - and there are are more important things to change like classes using spells they shouldn't, swapping out spell slots when you want etc. .
It's not the official rule. The ability to cast a leveled spell after quickening a spell is Larian homebrew. There are a lot of problems with the official sorcerer class, but this isn't one of them. RAW, you're effectively paying 2 sorcery points to cast a cantrip (or take the Dodge/Disengage action), which is not that powerful.
