Reasons to Restrict Multiclassing?

[malachi]

IKRPG = Iron Kingdoms?

Yeah, Iron Kingdoms RPG, or the full name is Iron Kingdoms Full Metal Fantasy RPG.

Thanks for the info! I'd be interested to see how something like that compares to 5e DnD.

More variety of character options in creation, less balance (comes from the lack of bounded accuracy, resulting in most races being able to stack either the chance to avoid attacks or their damage resistance to the point where even elite soldiers can't threaten them, but siege weapons can). The way 2d6 works, though, means that there is a much more reasonable probability curve for skills (novices and masters are both relatively competent at easy tasks, while masters are MUCH better than novices at epic tasks).
The way magic works (at-will, allowing so many points to be spent per 2 turns, rather than per day) allows it to be kept in line with non-magical methods of combat, and the system's focus on having almost only combat spells means that skills still get used at all tiers of play.