I don't believe I'll be implementing a system like that. I created subtypes of characters; just four. No need to measure the gaps of power between them even further. I'll likely set a standard and allow some diversity from it and allow creativity to only be leashed by a specific pool of vague resources and flexible descriptions, not so much a tiered system with definite units. 

Secondly, I don't do arena roleplays. Combat is fun, sure, but I believe combat is half pointless without context. On that note, I do have a system laying around somewhere that I worked with several others to create that actually makes a 'real' standard. The amount of effort put into it was atrocious, but it's founding principles were like so: all matter and energy are at some level equivocal, thus all things can be converted into a "unit" of energy or measured by a unit that can be converted into energy. For example, physics presently actually doesn't understand enough about electromagnetic forces or gravitational forces to make a formula to equate them; same with strong and weak nuclear forces. In such scenarios, any abilities relating to and thereof must be measured using a method that results in a unit that can be converted, eg if Magneto lifts a bus, what is the weight of said bus? Weigh can be converted into mass and kinetic energy can be used to equate overcoming the downward force of gravity. Anyway, it's a whole bunch of science. The purpose for it was that if you have a firemage, pyromancer, sun warrior that manipulates fire, they have to either create or manipulate fire, which would in theory result in the use of energy. Knowing the temperature of the fire, its size and radiant heat, you could calculate the needed fuel by using several different possible known materials, which would equate to mana. In most cases, you assume mana is "best suited" or "nearly optimal" for the desired effect, as per the effects of training. Anyway, the point is, you could calculate the actual amount of energy it would take to create and launch a fireball, which then could be compared to a completely different field, such as super strength that is lifting a heavy object. How much energy is needed for a fireball compared to how much energy is needed to augment strength? Again, it's terribly complex, but it's meant to be. It could be applied to ANYTHING and assured in almost every scenario there was a numeric value or variable that could be estimated for the sake of calculations. You can measure anything, literally, if you know the physics behind it. At that point, we would just cap energy amounts, set variables, create a metric standard for general energy; I believe somewhere there is a list of "tweaks" we made for conversions to kinetic energy and heat as well as other things for fairness, as practice showed that if you actually measure out some powers, they're far more unfeasible than others.

Back on topic, there's no real need for that level of structure, and if we do create it, I would prefer it to be in a more classy rank style such as Rank E, D, C, B, A (S) mutant or something like that, just for a standard of comparison. Still, there's a world of difference between that and tiered system. I believe as long as we know the standard "rank" our characters should be and their general character type, we should be fine.