Gruden is going to run a typical 4-3 Tampa 2 D in Oakland.
Rams are going to run Phillips' hybrid 3-4 in LA.
A 4-3 Tampa depends on a penetrating 3 technique at DT; they don't have one.
Phillips' 3-4 operates best with a top level OLB edge rusher. They don't have one.
I say see if Oakland wants to swap Mack for AD straight up. Yes, it would be complicated because in order for the swap to happen the players would have to agree to it and contracts would have to be worked out.
But......I don't think Gruden values an OLB as highly as Phillips does; nor does Phillips value a penetrating DT as much as Gruden does.
And IF (acknowledging that this is just my speculation) this is true, then I imagine the Rams would feel a lot better paying Mack giant dollars than they would paying the same money to Donald.
It's really not that much different than the Watkins/Cooks issue. The Rams weren't willing to give Watkins what they ARE willing to pay Cooks. Why? Cooks is the ideal fit (according to McVay) while Watkins isn't. Very good players, both. But....one fits the O better than the other, therefore the one that fits is worth more to the Rams than the other who doesn't.
Let's do the trade, pay Mack the money we'd have to pay for Donald, and then resign Suh longer term if the money works.