I'm between Lance and Troa.
At my table we proxy all the time. When I go to my local game store for a tournament, I have tougher standards.
The weapons do not have to be identical, but as a player I need some way to see it is that weapon. A marine with a big massive maul in each hand would be easy to recognise as a Marneus Calgar count as (or huge claws or jackhammers or even wraithlord fists instead of regular power fists (had a friend do this, and it worked...)etc). If you put a guy down with a sword and pointing finger...he's tough to recognize as more than a sarge. I like counts as, but usually you should model the mini to be close. My counts as
St. Celestine has a sword I painted flaming, and angelic wings. I painted her to have gold armor.
That matches my opinion of count's as. The key being my opinion. She isn't even based on a
GW mini and not legal in a
GW tourney, ...so I guess I'm flexible.
Now, I'm a big converter with a huge bits collection, and sculpts myself, so modeling
wysiwyg is part of the fun for me.