--I was originally thinking of a basic adventure for RMU that could serve as a starter adventure for the new system. If we could get ICE support we might be able to include some basic things like a few attack tables from the new system, so that these would be ready-to-play starter packs, of the sort that you've been saying RMU could use.
This seems to be the best route to take. Whatever starter adventure materializes it has to be RAW. We can't release an adventure for brand new folks and say "Here's this new game system we want you to try. Here's an adventure to kick it off, but forget what we have in the ruleset. Our play testers house-ruled A, C, D, and part of F. So you can house-rule those too, but we are still printing the core system as RAW."
We have to showcase the RAW and how it works. If the players want to tweak later, OK.
We had a similar thread to this a while back with regards to 3-4 PCs representing the base professions, 4-5 weapon tables for the weapons those pre-gens would be carrying. (I recall there was a debate on the Spear being included, then needing to include the Staff attack table too.) If we combine all of these great ideas into something that can be presented to ICE, I think we're on to something.
Starter adventure for RAW
4-5 Pre-gen PCs (Melee-type, Thiefly-type, Ranged-type, Pure Spell user, Semi-spell)
Stats for the Pre-gens at level 1 and at level 5
Weapon tables for Sword, dagger, bow, spear/staff
Crit tables for those weapons
We're looking at maybe a dozen pages and we have something we can really push out to players to let them sink their teeth into the game. Heck, I'd love to have that NOW as a beta tester! Cut back all the pages of details, rules, tables, and produce a "Quick Start" and let the players dig deeper into the system.