Concerning this whole "pact" issue, I think there is a difference here that perhaps is being overlooked?
Pact (big "P") = Warlock
vs.
pact (small "p") = Draconic Bloodline Sorcerer
The difference being what your PC is "given" and I think lacking a firm distinction between the two is a bit of a failing by the designers.
IME Warlocks, for instance, should really have their patron directly involved with the PC. The two made a bargain, magical knowledge and power for "
occasional services performed on the patron's behalf." How often and in what way the patron communitates with their warlock depends on the relationship between the two and the vision created by player and DM.
Sorcerers, on the other hand, have many ways in which magic was infused into their being. In the case of the Draconic Bloodline, being the first of a bloodline might involve a pact (again, small "p") or bargain as well. If your PC is the "
first of a new bloodline", and you are actually
playing your PC as a sorcerer, then the bargain has either been satisfied or perhaps needs to be (like part of the first adventure!). Either way, the magic is in your blood now, and can't be removed (at least not easily...). Of course, the dragon could always "enforce" the bargain if you welch--in which case your PC won't have a long adventuring career.
Over all, Sorcerers (if they have a "pact") due to their bloodline, already have the magic and it the bargain is likely done, but Warlock have an on-going arrangement with their Patron. Finally, Patrons are other-worldly beings, which depending on how you run your game, dragons usually aren't.
That's my take, anyway.
