I have said this before but since we are bringing the tweet up I will gladly say it again. There is no way that tweet is a MH reference/homage.
I am a fan of the MH series, I love to see it in Smash and a Hunter is my third most wanted (behind Isaac and Skull Kid) and I have various MH games but no. If it was a tribute to MH of some sort is just bad. There is no point of using that kind of angle much less if it is not in a hunting /fighting stance (since basically you can achieve this angle while hunting in game but is not used a lot for promotional art) but MORE importantly, there is absolutely 0 value on choosing that stage as a background. All of the MH fights are in the open, when it is in closed spaces it is still in the wild (caves and caverns for example) so why would they choose the Collisseum for a MH reference?
And also if it was a MH reference, why choose one (two if we count Link as S&S) weapon type only if one of the most important and unique things of the series is the variety of weapons? They could have thrown Pit as bow, Snake as a bowgun, or Kirby/King DDD as hammer, heck, they could have even thrown Palutena there as the insect staff or something.