Only an opinion from a "development class" sailor - both big boats and small.
The more rules you add, the more clarifications you need, and eventually the less development you have. Might add in that the more rules, the greater the desire to find a "loophole"!
"Traditionally" (from my experience ) Length overall, mast height (or sail area - not necessarily the same) and number of radio channels allowed (for r/c racing) provides boats that really are open for development. Anyone of these could be picked apart and argued - but you need to keep going back to the basics.....
1) Length Overall - this has been more than discussed for any handicap event, or development class. I'm sorry, but a 12" FOOTY is still a 12" FOOTY - whether it is in a box, laying on a table top, or floating in a box of water.
2) Mast height - Not sure of intention of a maximimum "minimum" rig ???
A boat as a mast height limit - you hang as much material on it in any configuration. If it's too windy, you hang a smaller amount of material. Everyone decides how much material to hang - and they maintain that mast height for entire race series. If you can reef your sail = bonus! (or you sail just like the ODOM Class - one rig, one sail set)
2a) Sail Area - now you start having to get into (more) complicated measurements. Instead of a ruler to measure mast height, you now need a calculator and knowlege of geometry to figure out how much material is hanging up there in the air. The 2 Meter multihull class specifies a mast height - and they don't care how much sail area you have/use.
3) Radio channels - self descriptive. Leaves the door open for ideas about mechanical trip wires, cams on one of the two servos, etc.
As I recall ( and was involved in way back when) the battery rule seems to already have gone by the wayside. "THAT" discussion also generated a lot of heat and bad feelings.
I'm sure that there will always be a statement .... "But what about ----?" if it's possible and doable, someone will try it. If it works - well, in my view that is "Development". If it doesn't work, someone will surely improve it - or ash-can it. It's kind of a self-policing effort. What works will be used, what doesn't won't and in the meantime, everyone can build to thier own ideas.
Logically, there might be other specs to be considered - keel depth, weight (minimum or maximum) number of hulls, rotating masts, movable ballast, etc. All these do is remove one more area of development for the builder. If you "WANT" to control everything - then a one-design class like the Laser or ODOM might be a better choice.
Again - a view from the outside when the class was first introduced as developments.