Sorry for the wall of text. I think you can just read the bold parts and have a coherent, 4 sentence post.
"We want every faction to be equally usable, as well as making every unit worth its price." -Blackheart (in the balance patch registration.)
First, I wanted to say I really appreciate the time you and/or your team put into that post and the ideas. I really like the post in general and I think you guys would make a great balance team. I'm writing this post not really as a criticism of what you laid out, but rather to use your sentence fragment as a starting point to reach a consensus/make a point that I've been thinking about for a while.
This post is about the concept of balancing units according to any sort of measure of effectiveness per price. In various balance related threads over the months, I have seen people doing this. One example I recall was in a discussion of how to buff aeon in the last patch, someone suggested that it would be illogical to buff the t2 hover tank to the point where it was equally good to the UEF non-hover tank in a land battle, since this tank can hover. It would be illogical, essentially, because this would give it strictly greater abilities at a strictly lower cost. Several people agreed with this point. I'll refer to this concept as a unit strictly dominating another unit. A unit strictly dominates another unit if it is at least as good by every measure of effectiveness, and it either costs the same or costs less.
I'd like to note that strict dominance is relatively rare in FAF. A lot of factors go into a unit's effectiveness in different situations. Percivals are a lot better than titans mass for mass (or at least so I've heard) in a head to head fight or against an experimental, but clearly are worse at killing an army of t1 and t2 units. Even if they were as good at killing t1 and t2 units, they're slower, so they still, if we're strict about our definition, don't strictly dominate titans.
There are clearly more complex cases that one could try to build. For example, one could try to show that restorer's dominate a mix of ASFs and heavy gunships from, say UEF by showing that mass for mass restorers have better AA DPS and better air-to-ground DPS than a mix of broadswords and ASFs. I feel like this would be an acceptable use of the term.
Alright, now that we have defined that term, here's the point. In my opinion, Units of one faction strictly dominating units from another faction is not problematic for balance. It's important that factions are balanced, but that does not mean that each individual unit needs to be balanced vis-a-vis every other unit. In fact, I may even go so far as to argue that having certain units in different factions be significantly better than counterparts in other factions may be a net positive for the game.
For example, if the aeon hover tank were better at fighting than the UEF t2 non-hover tank, AND it hovered, that would be okay. That would just give aeon a factional strength. LIkewise, one could imagine a situation in which the seraphim t2 bot is straight up better than the UEF t2 tank. It could be faster, have equal range, be better able to take on lower tier and higher tier units, and be about the same price. This also would be okay!
Or, maybe one faction has mmls that do a crazy split thing and are better than everyone else's MMLs, despite costing the same price (spoiler, this one is real). This isn't necessarily a problem (although I agree in fact this one may be a tad too powerful with the crazy splitting speed).
The concept of strict dominance is the extreme, but the point in general is that it's okay to have different units from different factions that are just plain better than each other or more cost effective than each other.
One might think this is problematic because it leaves no role for the inferior unit. This isn't the case because players playing different factions do not have access to the different units. In a world in which all my scenarios were true, a UEF player may still want to build t2 tanks, even if they were strictly dominated by sera t2 bots. Maybe he would against a cybran player who he anticipates is building 50% mmls and 50% rocket bots, or whatever. Even against seraphim, it would be a losing strategy to get in a t2 tank vs. t2 bot fight long-term, but a UEF player may still want to build some t2 tanks maybe with a little point defense to try to hold off a sera player at t2 while hurrying to t3 to try to get out some percivals or whatever. Or, perhaps imagine a world in which the sera bot is way better than the UEF t2 tank, but UEF also has access to a gatling bot, which outranges both units, has pretty good dps, and is also relatively low in HP. Maybe the UEF player would be willing to take on the seraphim player in t2, and would build a mix of gatling bots and t2 tanks, and would try to kite the seraphim bots. If the sera bots do manage to close, it'd be key to have some t2 tanks there.
Overall, FA has a disadvantage, relative to say, starcraft, in terms of faction diversity. Effectiveness per cost, while a good benchmark for thinking about units, should not be used as a reason to change the relative fighting ability of different units in different factions. Balancing should be done for factions as a whole. The goal is that no faction has a significant advantage compared to any other faction. There can be some units that are so powerful that they prevent this from being possible, but those cases are relatively rare. Having units that are more effective than other units increases faction diversity, gives the game much more variety, and creates more interesting strategic situations.
I will make the caveat that, within a faction, we probably should not have a unit that strictly dominates another unit. Because, then, why would you build the dominated unit? However, if it dominates it in most situations, but the other unit still has some capabilities, that's okay (sera t2 bot being way better than hover tank, but hover tank can hover=not necessarily problematic).