IMO they are going to retain Finley so if you don't like him you should want him franchised - that would give him one season to prove himself. The other most likely scenario is they'll sign him to a multi-year deal. He's going to be 25 years old in March. McCarthy knows him much better than anyone posting here and he REALLY wants to keep him. If he matures - an "if" I know - you don’t want him playing elsewhere.
I'm surprised few know how the tag-and-trade deals work, particularly since its been explained on this site. Here's the process: The Packers tell Flynn's agent they're going to tag him and they want to trade him. They tell the agent what they want in trade and probably tell him not to contact the Vikings (the only team in the division that may be interested). The agent then contacts all the interested teams, negotiates a deal with the one willing to pay the most money or the one Flynn prefers. If a team, like Miami, thinks he's of starting NFL QB quality, they'll offer a contract with at least $14M guaranteed - over several seasons. If the Dolphins, for example, want to avoid a bidding war for his services (that's why they'd trade for him), why wouldn't they give up a second rounder (if they have one), for example? Another factor is Flynn wants to be a starter in the NFL and knows he won't get that chance in Green Bay.
If he wants to join Philbin in Miami and Miami is willing to deal, why not? Flynn gets his chance to start in a system he knows like the back of his hand. The Dolphins get what they hope is a great starting QB for a second rounder. The Packers get a pick in the first half of the second round instead of one at the end of the third. Win, win, win.