it's easy to formulate the requirements of proper balancing. 1) No mech should be "better in any possible way" than any other mech of the same weight class (example: Arctic Cheater). This is a problem right now. When did you see your last Awesome in the wild? Or a commando that didn't suck? 2) IS and Clans have to be balanced. This must not be accomplished by power creep (quirks), but by nerfing clans a bit. "A bit" because clans are not that OP anymore. I really do drive clans and IS alike, and the only mech that bothers me is the arctic cheater which is borderline OP no matter what, and still its fanbois deny that. But it is. 3) The power creep has lead to alpha-warrior online, and the current meta is boring. Incredibly boring. PGI has realized that and the recent activity regarding the rebalancing is very interesting and will completely crush everything we currently know about the game. This is good! Give them a chance. It really is that easy in my eyes. And nobody has to pre-order all the packs, the come out for c-bills eventually. Nobody in my unit requires me to have a 'mech that is only available for real money. And we do competitive stuff.
This concept of massive amount of IS Mechwarriors VS a relatively small numbers of Clanners worked in the SP Campaign Mode against CPU Enemies. But translating this 1:1 to a Massive Multiplayer Combat Game, where the MAJORITY of the Real Players pilots Clan Mechs - any Approach to balance this PGI's Universe fairly is doomed from the beginning. 12:10 would require a 1,2:1 Distribution of IS:Clan Players. But the Reality is quite the opposite, maybe even more drastically than 1:1,2. The only chance PGI has to even the Distribution is to give Players real good reasons to chose IS Mechs/Factions more often than Clans. You need to make the Factions very special - unique, so to reflect their Mentality and Combat Style on the Battlefield. E.g. Faction specific Bonus/Quirks/Customization. Make the Players identify themselves more with the given Factions. Atm it's still quite the same whether you chose this or that House/Clan. If this stays the same, the Player will simply chose the better Mechs.