So, some thoughts from a live run through: one of my table had played Rolemaster 30 years ago, and it brought back fond memories for him: I found it nice and simple to run: I appreciated the variety of damage types (although recording that for each of my monsters proved a wee challenge as ever). We only had time (in four hours) for one substantial combat, and that was a fight between level 10 characters and some pigs. The pigs were not much of a challenge, but an open end roll got an E crit on one of the players.
Despite doing some revision, I'd forgotten some rules (mainly how shields work now), but I found the book easily navigable so it didn't take long to look them up. Looking back, it seems I missed the new rule about skill ranks reducing fumbles (it was a fumble fest, but every kind of enjoyed that). I also missed the absolute hit rule (I knew there'd be some sort of extra damage beyond maxing out, but I decided not to look it up to save a bit of time, on the grounds that it wouldn't really matter). I also misread the charging rules (had I read any rules correctly?)
There wasn't much chance to see if I'd made any errors in the level 10 characters I'd built, save perhaps I should have paid a bit more attention to some secondary skills that I knew would be plot relevant. Turned out the Magent I'd built was awesome.
Finally, none of the players had played RMu before, but they picked up what they needed to do pretty quickly. Will run again.