To add a few thoughts: With the game's recent revival (and the revival of online multiplayer), people have been talking about reviving this game for speedrunning in a more official capacity (i.e. through this site).

There is currently an effort to recreate the lost aspects of this game, specifically in the online multiplayer mode, to make it as close to the original experience as possible. This means recreating things like the old online event and arena quests, which were lost to time after the original server outage. The arena quests especially are built for trying to complete them as fast as possible with either 1p or 2p, so they are well suited to the speedrunning format.

As one of the MH3SP server devs, I've recreated a number of event and arena quests and am actively recreating the remainder. I can't guarantee that the quests are byte-for-byte exactly like they were back in the day, since the positioning of things like small monsters and the giant dragonator-blocking rocks relies on floating point coordinates and rotational angles whos exact values are long gone. However, most of these differences are largely inconsequential, so I still believe the category can be preserved and doesn't necessarily need to be split into "official server" and "new server" groups. As the recreator, I am readily available to be consulted for case-by-case situations where a quest might have a more significant difference between what it is now and what it was in its original state.

Additionally, it would be possible now to have active speedrun categories for milestones in the online multiplayer mode itself. For example, a category where the goal is the HR30-31 urgent quest to fight Jhen Mohran and unlock High Rank, or the final urgent quest at HR50 to fight Alatreon. These are things we've had discussions about at length in the Monster Hunter Tri discord server, and a lot of us are excited to try now that it's finally possible to access Loc Lac and all of its content again.

Thank you for reading,

SpyRo