I won't lie, if Fennekin does somehow end up being Fire/Fighting type, I'll be the one dying of laughter out of the sheer irony of it all as Fennekin's extreme popularity drops in mere seconds simply because of a dual typing that has been around for three generations in a row. But I have to agree, I am also getting tired of the typing by now, as much as I love Infernape and to an extant, Emboar.
But in all seriousness, I don't really think Fennekin will be Fire/Fighting. A lot of fans are theorizing that it will be Fire/Psychic. Of course that's just going to make people complain that "Oh great, it's even more similar to Victini now."