I remember that way back (late 80's or early 90's, though I could be wrong), one of the guys said that they'd probably go up to 15 albums, and now that #15 dropped with TFF, maybe some fans took those words to heart.
I like the idea of When the Wild Wind Blows being their swan song; it's one of my favorites from the album. That in no way means I don't wanna hear some more from these guys. I mean, this if fuckin' Maiden. They probably contributed the most to my sense of music as it stands today. As far as I see, I think another album is likely, and anything beyond that is up for debate. If they had intended for TFF to be their final album, I think we would have heard them make a pretty clear note about it, and it would have been a pretty big deal.