Does a Sorcerer have access to the best spells to exploit disadvantage? No, she does not.
There's so many cool tricks you want to play with sorcerers (Careful Evard's Black Tentacles! Black Dragon Sorc with Melf's Acid Arrow! Heightened Planar Binding! Extended Animate Dead!) and then get stymied because (among other reasons) it turns out they can't know the spell in question. Nobody even really knows why their spell list is as narrow as it is, because WotC doesn't explain their logic. Would it break any design considerations if you just gave sorcerers access to the wizard spell list? Who knows? At least in the DMG we get the explanation that spell slots are the default spellcasting method because WotC considers them "simpler" than spell points, but when it comes to the spells actually on the lists, we're in the dark. It looks as though Sorcerer spells could have been chosen (1) to keep them simpler, "intro" casters who don't have many complicated spells or decisions to make, or (2) to minimize metamagic synergies to prevent sorcerers from breaking game balance. WotC never says which one it is, and when they add new spells like in the EE Players' Companion, they also don't explain why certain spells are given only to wizards and druids, or only to warlocks and wizards. This occasionally raises a third suspicion, that (3) it's completely haphazard.
The cleric/wizard divide is pretty clear for historical reasons: only clerics can heal, only wizards can efficiently throw huge AoEs like Fireball, and other than that it's okay for them to overlap. Since sorcerers are a new thing, there's no history to guide us.
Honestly it would have been better for sorcerers to just draw from the wizard list.
