It's since added new content to the game, so it isn't strictly a balance mod anymore.
There are actually two versions, one with new content and one without...
While on the whole it seems like a nice idea, there are two major flaws with such a project...
First, lack of consensus...certainly a mod can be used to try different things, but some game mechanics are just broken and beyond mere tweaking/balance...
I'll give you an example...animosity simply is an awful ability...most nearly all players agree it needs a secondary effect...however, it's very difficult to agree on what exactly that secondary effect should be...the issue is that more than just mere tweaking is needed to make this ability useful...so, more opinion and less actual balancing becomes relevant here...I finally committed to adding a DPS effect (like the passive ability on the Destra Crusader), but others advocated things like an accuracy or weapon cooldown penalty to affected ships...
In truth, both ideas could be perfectly balanced, but then which one is right? That's where things get tricky...ultimately, the mod only because a test ground and could never be implemented for the community as a whole...I mean, imagine trying to get consensus on how to properly balance mines....it would just be a nightmare, far easier if individuals simply post their own changes and people praise/critique them...
Second, many changes in the mod become obsolete with new updates...for example, v1.3 of diplomacy will include completely new pacts...not just rebalanced pacts, new pacts...this renders many of the potential changes for balancing the current pact system completely useless...this doesn't mean a balance mod can't be made now, but it certainly hurts one's motivation when they know in a month (or week) that all their work will be obsolete...
There are clearly some advantages of community work...many changes in the last update were tried in Project Equilibrium...for example, the Jarrasul's colonizing ability spawning extra constructors (and I believe it was Darvin's idea to try that)...
However, that same ability also shows how pointless such community work can be...Project Equilibrium had that ability completely working before the devs released Diplomacy v1.2...however, the Dev's initial release of that patch was bugged, the Jarrasul colonizing ability caused a mini-dump when used...we ran into the same problem with Project Equilibrium and fixed it...why then didn't the devs release a non-bugged issue? Why did it take them a while to fix it when they had a working version right in front of them?
Maybe it was just an honest mistake....or maybe a lack of communication....or maybe the result of a time crunch...
Or maybe the devs didn't actually look at Project Equilibrium at all....
Bottom line is, such a project would need confidence that it would be taken seriously...
Project Equilibrium is not dead...I have been testing changes of my own for quite a while, either with LAN games or with using the dev .exe files so I can pit fleets against eachother...
In general though the project fell apart...the ICO community is small, the mod had very few downloads (I think it peaked in like the 60s), and testing it takes time...furthermore, there comes a point where people will accept the game as "good enough" and may scoff at the idea of a balance mod (even if there are small balance issues)...
I for one won't be posting any improvements to Project Equilibrium until after Rebellion comes out...that's a long time from now, but I simply don't have the time or the will to do such an endeavor when I know I'll have to do it all over again as soon as Rebellion is out...furthermore, how many more updates to Diplomacy before Rebellion?
In general, mod projects should suit you...they should embrace changes you like since all that matters is what you enjoy...since PE had very few people, I've mostly moved on to trying changes for just me and my friends and our LAN games..