Seriously, ya'll need to watch this version of the trailer:
https://www.youtube.com/watch?v=xe-RAeDfOMM The editing and new bits show that it is very much a traditional monster hunter game. It adds on 4th gen mechanics (jumping and landing off cliffs, mounting, climbing and more)
For those who think this is a side game its not. It is being developed by the main series team (MH 1, Dos, Tri, and 4). It is the first 5th gen game.
Sources: Famitsu:
https://www.famitsu.com/news/201706/13135277.html
Interview:
https://www.youtube.com/watch?v=W62j4xfq_yQ
The interview confirms it and my Japanese source has as well. Capcom's main MH website advertises it as the "Next Monster Hunter Game in the series". You can even look this up on the English version of the website, not even Generations was considered the "next" in the series. The fact that they are showing a simultaneous release for the first time as a feature just spells out main series release. That being said, feel free to verify.
Also, for those who don't know, there are only 2 monster hunter development teams creating games under the main series title. The "B" team creates MH Portable and X/XX series, and will likely continue making traditional MH games in this fashion for Nintendo consoles (this is a guess). The "Main" team has made the other, main numbered titles. This is considered a main game, and since the "B" team is focusing on XX Switch Ver. atm, the Main team is the only other dev team working on this. The Frontier and Online teams are totally separate from these two. There is no 5th team, this is basically Monster Hunter 5, created by the Main development team.
Last thing: Capcom CEO Ryuzo Tsujimoto doesn't personally come out for an interview to advertise his baby if it wasn't a main series game (check the youtube link).