User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-184.38.6.64-20120131225239/@comment-70.54.115.32-20120131232047

I don't think the development team cares that deeply about the game's story. There's some far simpler explanations for it.

1. Portable 3rd is an "evergreen" title: it's been selling well for a long time, and it's still making money. By leaving some monsters out from Portable 3rd (especially the popular Tigrex) there's still a reason for people to pick up that game.

2. While assets are being imported from the Wii and PSP, they are modified to fit the 3DS and share the same look as the other things in the game. These monsters may have been left out because there was not enough time or budget left for this work. It's pretty obvious that 3G was a rush-job to get the 3DS programming experience, game engine, and cash to invest in 4.

3. Space. While Metal Gear Solid 3D and Resident Evil Revelations use a 4 gigabyte game card, Capcom decided to only use a standard 2 gigabyte game card for Monster Hunter 3G. This is about the same size as a double-sided UMD. Monster Hunter has never pushed to the size limit before, but Tri was well over 2 gigabytes. 3G has very similar graphics, much more content, and a different engine, so it's possible that they were closing in on the limit this time.