Oomis:
I’m with you on this one. The two parties should be mature enough to break it off by themselves.
If the strife is cause by third parties, and these individuals are truly right for each other, than one (or both) should get up and say something, show a little back bone (which in these days is probably non-existent regarding the engaged couple since they are usually 100% dependent on the parents, and will be for years).
Thinking about it, the shtar is kindof useless. Feelings do not go away because someone wrote something. Also, having a stigma on you because you won’t write this shatar is tantamount to blackmail, which as you said “is wrong in so many ways”.