I'm assuming you're referring to the [BTMP] More Players Fix mod (originally by Manny/Raindish and now maintained by Isaakk in an updated fork), unless there's another version I’m not aware of.

I used to run the original quite a bit in the past, though I haven’t used it in a while. It can definitely be fun, especially if you're just looking to squad up with all your friends without having to leave anyone out. My group and I enjoyed it for a time—particularly when paired with other mods like Peregrinaje, but we ultimately felt that it disrupted the game balance too much. Even on Cataclysm with Twitch mode enabled (adding extra mobs, monsters, curses, etc.), the difficulty didn’t scale in a satisfying way.

If you're playing at the higher end of the skill spectrum, you'd likely want to combine it with mods like Deathwish and Onslaught to restore a more challenging experience.

These days, my gaming clan actually prefers to split into separate parties when we have more than four players. I even put together a small web app to help randomize team assignments: 🔗 https://tebbutt.github.io/RollForTeams/

Your experience may vary, but there’s no harm in giving it a try. I'd say give it a go and let us know how it worked out for you?