I'm up for this, but I think faith in any new ruleset will derive from the why as much as the what.
We are not short of compendiums and total conversions that range from the small edits/collections (such as wyldhunt's recent version, and the example you cited) to the full on new systems (coreheim etc)
I like what you presented there as making the justifications/changes clear. Breaking the rules into sections that we can propose changes with explanations would be good (maybe a googledoc with columns could be a good start?)
Personally as a player of mordheim, I struggle to have confidence in the rules unless I am confident in the source, or at least understand the agenda behind them (ie is it balance, roleplay, complexity, simplicity etc).
Does Necromunda CE still derive from 40k second edition like the original did? Or is it based of a more recent 40k edition?