I might sound mean here, so I apologize in advance. Here's my answer:
I, personally, wouldn't mind a guest character. Everyone else, seems like it's a no.
Another fansite I go on blew up like crazy with a bunch of immaturity over one measly guest character. I was so shocked to see how many crying babies there were just because this character was announced to be the last DLC for Mortal Kombat 2011. Then there were the whole, "If anyone plays Freddie against me online, I'm just going to immediately quit" and that downright pissed me off.
If people are so uptight about one guest character, and I do mean one guest character, then why bother giving a fan base a little gift or whatever? And granted, I shouldn't base every single fan based on one site, but I mean, how can you be so ridiculously immature over people liking the fact that this guest was playable? People were literally saying to others that they're not a true Mortal Kombat fan if they were to like Freddy. How in the world can you base how much of a fan they are over who they like and don't like?
Seriously, I would definitely like to have another guest character. I don't mind it, but I just cannot let go of how idiotic so many people were back in 2011 when Freddy was announced. That was just downright pathetic.