Organiser, Serenity LRP

It seems to me that you just want to make a straight substitution of numbers for descriptive terms.  My first question would be what your objective is for making this substituion?

One major benefit of a change like this would be that a PC could interact with a task (say fixing a Warp Drive as a nod to Override ) and use the rules-based terminology while roleplaying to quickly indicate to a nearby ref what their skill level is, so that the ref can deal with making a call, rather than requiring the PC to (at any point) drop OOC to describe to the ref what their skill level is.

Another would be creating a simple means of communicating skill levels between players IC "I'm a journeyman alchemist, whereas my buddy Bob is a Master".  If done carefully, those without the skills will have no idea what this means, but to another with the same skill (who understands the jargon), it'll have a meaning.  This would translate into PvP task resolution (such as an arm wrestle in a soft skills system) allowing IC roleplay to indicate to both parties OOC who should win.

Assuming that this is your reason for this system, I'd suggest creating a number based system, and then making a straight substituation for descriptive text.  When a player 'Dave' takes Alchemy 3, he's told he's a Master (and that level 2 is journeyman and level 1 is apprentice). If he meets Bill the Alchemist, and they interact, Bill may reveal that he's a Supreme Alchemist.  Dave has no idea what stat level this equates to (could be anything 4+), simply knows that from the techniques and jargon Bill uses - he's better.  When Dave goes to level 4, he becomes a Supreme Master Alchemist (and realises that Bill must be pretty darn good at Alchemy).

This will allow better IC interaction, less overt ref interaction, and still allow you to keep simpler number records for the refs and crew to refer to.  The complication is that refs will need a good knowledge of all these terms to work effectively, and some players may see it as overcomplicated.  It will also make bluffing your ability to other PCs far harder IC.

Obviously the example above is a simplified idea with really rubbish terms (as I really can't be bothered to try and think of any good ones!)

"Plan B is we swear fealty to the Dark Lord."

I liked your example, but why will it make bluffing harder?

And why do blunderbusses have rounded ends?

Surely the best thing to do if you don't like numbers being shouted out on the battlefield is to either:

a) remove them from the system

or

b) come up with a reason people would shout them.

"Plan B is we swear fealty to the Dark Lord."

Because if you are a Master Alchemist and someone else also claims to be Master Alchemist (or any alchemist of a lower rank) you can either try some alchemist jargon on them and see if they understand, if they understand they likely ARE an alchemist.

Or if they is a naming convention that alchemy follows (Student - Lecturer - Professor - Dean, for example) and someone claims to be Uber Alchemist you can look at them askance because they do not follow the pattern and are therefore probably making shit up on the fly and hoping you don't know either.

crazy yank

Ahh... so bluffing won't just be a case of "[insert patent untruth here]" and people being too nice to believe them?  In which case, I'm all for making it harder, people are too ready to believe in LARP and where's the fun in that?