Maybe I went a bit overboard with trashing the double trashing argument.
My maxim is more around the lines "make sure you get a source of money at some reasonable point". Ambassador and chapel both have this weakness of basically making you skip your turn when they are most effective (double/quadruple trash). It's a powerful turn, but you can get royally screwed if you're not careful (or get disrupted: militia hurts a hand with ambassador + 1 estate +1 silver +2 coppers).
Trash for benefit are great as secondary trashers: apprentice, bishop, remake, remodel and salvager all work really well with chapel/ambassador as your main trasher. Bishop is probably the best because you're really using the fact that the other guy is probably also trashing like mad and not getting the benefit from your bishop. Though salvager/remodel have something to say about getting you out of the money trap.
I'll happily get a salvager to complement my first ambassador rather than a second ambassador. I'll only ambassador coppers, and salvage estates. If the other guy ambassador's his coppers, he's not going to lift off the ground any time soon, and if he just ships me an estate a turn, I'm completely fine with that.
It's a very specific example, I agree.It's just that for newer players, reading lines like "open double ambassador" can be misleading. They will not play it out properly, even when it is the right call to make.