I think the approach to faction diversity that the current balance team took in patch 3655 Beta is counterproductive. Below I will try to explain why in a short manner. I also put up some links to related game design articles if you are interested. I apologize for not going to much more detail about the concepts, but I'm sure you will get the gist of what I'm talking about. I trust the balance team to reconsider the direction they are taking with faction diversity based on community feedback that is coming in abundance.
If a unit costs the same amount of resources and fills the same purpose its stats should also be the same.
What is faction diversity
The aim of faction diversity is to create interest in the form of gameplay variance. We want each faction to feel and play different and offer a different array of choices for each matchup to keep the game fresh and interesting.
How faction diversity was implemented in 3655 Beta
Factory HQs, T3 Mexes and Walls were given significantly different hitpoints. Cybran getting the least, Aeon and Seraphim about the same and UEF the most.
However
3655 approach creates very little interest, since the difference in gameplay opportunities is negligible. Essentially the role and purpose of each subject has remained the same. They are used in the same way, in the same situations, to a varying degree of success.
Besides the lack of faction diversity provided by the changes, they also introduce a number of problems;
Intuitiveness
They look the same, they feel the same, they smell the same, but they are not the same. It's difficult for a player to differentiate between things that are so similar in every way. The unintuitiveness adds in a big way to unfairness and burden of knowledge that are described below
http://www.gatheryourparty.com/2014/11/25/getting-to-grips-with-intuitive-design/
Fairness
Having an unit/structure fill the exact purpose of another while being objectively better feels unfair, even if the factions are balanced as a whole.
http://www.whatgamesare.com/2013/01/choose-fairness-over-balance-game-design.html
Burden of Knowledge
Learning how many strats you need to kill mexes for each faction individually etc. forces a lot of unnecessary memorization of trivial knowledge
http://forums.na.leagueoflegends.com/board/showthread.php?t=293417
So what should be done instead?
When diversifying the rather homogeneous unit base of SupCom it's a good rule of thumb to make each unit a tradeoff: a unit that is better than it's counterpart in one respect, should be weaker in another.