"You never know who Danny might be able to turn that into that would get the team younger while still keeping it contending for a championship. Maybe Philly wants to get out from under Dalembert and Iguodala's contracts. Maybe Phoenix wants to go after a couple of big names and wants to deal Jason Richardson and Leandro Barbosa. Perhaps Dallas needs to get into the market so they deal Howard and Terry. Perhaps someone you wouldn't expect to become available will that Danny could package these guys for."
Nick, were those example of trades you would be in favor of, or were you just throwing out ideas? Iguodala and Dalembert both have contracts I would want no part of. I also see both of these players as one dimensional. In my opinion, neither of these players have ever lived up to their expectations. I would not trade Ray Allen for them.
I think Richardson is a fine player, but I do not think he would fit into the Celtic offense. Barbosa is a great bench player, he could probably win 6th man of the year with us. But I would not be in favor of paying a bench player seven million. I would not trade Ray Allen for these guys either.
Jason Terry is 31 years old already, he would be 32 when the potential deal would happen. From what I have seen of Dallas, Terry is already on the decline. I do not consider Terry to be anywhere near as good as Ray Allen right now, so why would Terry become better when he is already past his prime? Josh Howard is fine player, however, in my opinion, he is a career overachiever. Howard may also be chronically injury prone in the future. His game is also a bit redundant with pierce's game.
If this is Ray Allen's trade value, I would be in favor of extending Ray for two more years at 10 - 12 million a year, and extending Pierce for an additional year. This would give Boston the room to add young mid level exception talents.
I would have to get a deal that would really blow me away to trade Ray Allen. Because I think he will be a better player than the players you mentioned for another 2-3 years.