While I enjoy the Sorcerer and Warlock classes for what they are, I've sometimes wondered if they'd both be better off smooshed together into a single class.
Pacts with planar or other-worldly powers seem....well, remarkably inconsequential as implemented for the Warlock. I mean, honestly, something like that seems like it would be rather significant (especially the idea of, say, a devil offering some 0-level nobody a chance for magic powers...that one strikes me as truly strange....not implausible entirely...just a little odd). Pacts like that suggest an entire subsystem that any class could acquire.
The Sorcerer's entire schtick is natural ability to cast spells (manipulate the Weave or whatever your preferred fluffy flavour) instead of having to learn them through study, as the Wizard. Metamagic seems....rather an odd thing to be exclusive to Sorcerers. I mean sure, they need more than just innate ability to wave their hands about, speak a few arcane words and
poof! a spell happens. Kinda the same as Warlocks, they just know even fewer than Sorcerers and can cast them less frequently before needing a breather.
I dunno...they just feel like they'd work well if they were put together. Or not. Just mental diarrhea happening here perhaps.