Brooklyn Rangers Fan
Change is good.
We have little depth on the RH side. Just McIlrath. After that its taking lefties and forcing them to play the right side.
Allen is a skilled RD despite being a lefthanded shot. (Now, the fact that the Rangers have historically preferred righthanded shots at RD is a separate question.)
The Rangers have two guys who are near ready to play (neither at a top pairing level, but that's the sacrifice you make if you are retooling). They are Allen and McIlrath. The former can play both sides and the latter is a RD. (Interestingly, I personally believe that Allen is ready and McIlrath needs more work.) After that, they have Skjei, who is likely 1-2 years away, Noreau and Andersson who are 2-3 years away they make it, Graves and Donnay who are all 3-4 years away if they make it.
It's not phenomenal depth, but it's enough to trade 2-3 of Staal/Girardi/DZ (especially if you get some defensive assets back), IF you are willing to accept that this year and potentially next you will be out of contention as a result of retooling.