Delving as little deeper, there are times when proxy models can't be avoided. If you want a game and just can't get the models you need, or can't afford it, or it's currently on the workbench, fair enough. You might want to try out a unit or character before you go and buy the models. Again, no worries. It goes without saying this applies only to friendly games. Try turning up at most tournaments with an inappropriate proxy model. This is NOT the same as counts as, in my book. Counts as allows players to let their creative juices flow. I've seen great themed armies with superb counts as models, such as Dan's/Nyhil's wonderful skaven as dark eldar at Ten Inch Template . I play an undead cyclops as a vargulf. Now he's on the correct size base, is about the same mass, my opponent knows the score, so all is good. Proxies tend to be hasty stand-ins.
|"That's a what now?"|
Which is exactly what I've been doing with my skeletons. Sigh. The ghouls are on the bench to take over, but every game the silver skellies make me wince.
I think it ultimately comes down to a respect for your opponent as well as a desire to build a beautiful army of miniatures. If they are willing to play you with their painted army, fleet, warband, legion or giant robots, then you should answer with the same, if you can.
Back to those ghouls...