The only way I could see it being a good idea for the GM's to play the game is if they were to play on an isolated "test server" where they were in no way put in competition with the regular players. And that would pretty much defeat the purpose of them playing, as 95% of this game is community-oriented
95% ? sorry not true.
the problem is that the GM needs to reply on several tickets. If they get a ticket, they do an action while not having enough background information. it is not hard to use the search tool or poke a GS which should take 1~2 mins and more customer happiness because they don't have to reply on their ticket about a mistake, missing items or wrong bans.
recently, when i was a GS i had a case that the GM was constantly saying that the item isn't in the WH ( for GM enchant ) while it does. reason : the item was a bugged item, it was showing pants instead of boots. it was stated in the ticket but somehow it got overred.
i shouldn't talk about other game publishers, but they really know almost all kind of bugs/glitches a game has while aeria even didn't knew about the gear bugs. and that while the gear bugs is a common and accepted fact