Free-to-play games have to make money somehow, and character customization options are usually the option that developers pick just because it’s possible to add options in there that aren’t going to horribly unbalance gameplay. That’s fine; we accept that. It doesn’t bother me if, say, a game puts new haircuts in the cash shop. But it does bother me if a game only adds new haircuts into the cash shop, or locks and entire vector of expression behind the cash shop. If I have to pay five dollars to customize my character’s height, I am beyond annoyed.
And games like Fortnite that lock even basic appearance customization behind the cash shop? Thanks I hate it.
It goes without saying that there are games that do this and are still successful, of course; look at the example I just cited. And these are not the only red lines that people could have. It’s possible to treat the inclusion of a ridiculous out-of-place costume as the red line, because that proves that the game will just sell you a look that makes no sense in the setting. Or maybe your red line is particle effects that make the game more laggy. What’s a red flag for you for MMO cash shop customization?