Arguing Undead dont breath to avoid a rule which is just plain stupid, while fluff wise he has a point it wasnt against the spirit of the game, he was just being awkward. The only rule similar to that which is something you can legally argue but never would as it is totally against the spirit of the game is in Warhammer. Models that doesn't have two or more eyes, can never perform any action that requires LOS, as the rule for drawing LOS states it must come from the models eyes. So undead, some Skaven models, Gorgers and a few other models can never charge, cast spells etc... Would you argue that, even though the rules say you can? No of course you wouldn't, why? Because its against the spirit of the game and clearly poorly thought out. It's so against the spirit of the game I've never hear it being brought up. It's not the only rule which is poorly thought out either but we as players are expected to work around rules which are that bad.
If someone takes Fame for Murder against Pandora, how about killing it with minions and not having Pandora hit it with 15 different Wp duels each turn? God a shock, Pandora having to think a bit before hitting everything with Wp duels and relying on her crew to do something for once.
If someone grudges a model they know you are going to kill as part of your strategy, such as a Canine remain then that is their fault, it was a poor choice on their part. If they grudged a model and you simply kill it off (even though you would never normally do such a thing) then that is against the spirit of the game and it is you just playing in a WAAC manner. Your argument, to me at least, comes across as 'If anyone ever takes Grudge, Kill Protege or Assassinate then they are stupid because I will just kill off the model before they get chance so they cant get the VP for them.'
I admit the schemes aren't perfect, and yes a fair few of them need tweaking as they were intended for book 1 models. Perhaps we should let Wyrd know we think some need tweaking and maybe even a couple of new ones?