Unlike the OP, I Think the Loremaster Wizard was outright broken; making the Sorcerer superfluous was a mere afterthought. 
I will agree that the Sorcerer, while competent, feels a little awkward and restrained. However, I don't feel the solution is to take new-vancian casting away from other casters so sorcerers can be unique again; they just need more unique things to do.
1) I would allow them access to more meta-magic earlier in their career. I had thought about given them the ability to apply Subtle Spell for free at a certain level, as long as they had at least one Sorcery Point left. But that might be too much.
2) Only allow them to use Flexible Casting to make more spell slots once per long rest. This would open up opportunities to recover Sorcery Points outside of a long rest without giving them unlimited stamina. They could then recover CHA mod Sorcery Points per short rest. Perhaps subclass' could give unique options to recover as well (On Wild Magic Surge, gain one SP).
This would at least given them more room to perform their shtick without giving them unlimited stamina or overpowering them, IMHO.

I will agree that the Sorcerer, while competent, feels a little awkward and restrained. However, I don't feel the solution is to take new-vancian casting away from other casters so sorcerers can be unique again; they just need more unique things to do.
1) I would allow them access to more meta-magic earlier in their career. I had thought about given them the ability to apply Subtle Spell for free at a certain level, as long as they had at least one Sorcery Point left. But that might be too much.
2) Only allow them to use Flexible Casting to make more spell slots once per long rest. This would open up opportunities to recover Sorcery Points outside of a long rest without giving them unlimited stamina. They could then recover CHA mod Sorcery Points per short rest. Perhaps subclass' could give unique options to recover as well (On Wild Magic Surge, gain one SP).
This would at least given them more room to perform their shtick without giving them unlimited stamina or overpowering them, IMHO.