Do you think VC/TakeTwo should try one last time to compete with Madden? I think All Pro failed because it didn't have the best support or budget, and felt like those early 360 games (Gun, Tony Hawk) in that it was just an upscale of NFL2K5 without the corporate logos. They also booked on retired stars, the easiest go to idea, and least interesting. They didn't deliver a lot of star power anyway, a lot of 90's stars were still playing. Nowadays they could've got Farvre, Lewis, Hines, Moss, TO, etc. Blitz the League went to far into that ESPN PlayMakers show territory. We just wanted the violent tackles, not storylines of off the field violence and roid use.
Anyway, Madden has since turned stale, NFL2K5 is so old they'd have to build a whole new engine for XONE and PS4, 2K Games is leading the sports market with NBA, but recently lost its once upon a time critically acclaimed MLB and NHL games to a resurgent EA NHL and "The Show". Adding WWE2K14 to the mix was a huge deal as its got a loyal fanbase who many would rather play that game than settle for how the stories go on real TV. And it has no competition.
And now they have a relationship with a company sitting duck on its own football league, in which any money recouped would be welcome, a game that resembles NFL enough (unlike Arena/Blitz) with enough added flavor, and no need for the game programmers to come up with team names, logos, stadiums, or possibly even fake players. Football is popular enough to warrant a second game in the genre, if expectations were right, XFL 2K15 could offer football fans what WWE2K offers wrestling fans, something that lets you do things your way (whether that be compared to what Madden forces on you with trading cards and paywalls and lack of innovation each year, or the real NFL on TV not having the best pacing or action to boring plays/commercials/boring announcers ratio.)