Well, Rome offered the AA, the SSPX refused it. I dont think you can consider an offer from Rome to be anything with regard to the intent of the SSPX. You can consider their refusal to accept it, but that is more evidence of an intent to build a separate Church.Would granting an annulment be sufficient? That is done by a tribunal, of course, and the SSPX has established one to do just that.It's certainly evidence of an intent to build a separate church. Negotiating an apsotolic administration with Rome is evidence pointing away from that.
As to continued negotiations, I do consider that a good sign, but I note that the various Orthodox Churches are also negotiating, as are various Lutherans, etc. They certainly have separate churches (depending on how you define Church for the Lutherans). In part, that is one reason why the negotiations are necessary.
patent +AMDG