Cyborg is essentially correct.
SBR follows 4X models of 'gameplay', and I approve of v3 because the econ and combat models feel good for a 4X experience. Not too fiddly or miring an experience, moved econ development front and center rather than hidden behind the screens of screens, scrapped the tedious unit shuffling across the game board that isn't as rewarding or impactful as people like to think it is, but still adequately involved.
Now all those things need some polish and refinement (especially combat to reduce the click-spammy nature of it at times), but the first half of a 4X game is present. That is, being able to develop your power base as a player.
What's going to make or break SBR is the challenges SBR manages to muster against the player ('s power base) and what the player is able to do about them. To that end, read the updated game description on Steam. Chris conveys the missing half of the game in what amounts to a shorthand design doc there.
What worries me in regard SBR's success is the ambition of that game description, and that significant portions of it aren't yet in the game released to us testers.
For example - Events do not currently offer a challenge or an effective model by which a player's citizens/"internal threats" can screw everything up on them (per Act 1 description) and then allow the player to respond to those challenges, hence my suggestion for Events v2 on mantis to correct that. Disease tweaking would be an offshoot of this too.
Being able to interact with other AI races via building abilities is frameworked in but also needs to be fleshed out fully and tuned to the game's economic model (or vice versa) as a second example.
And then the rest of the Act 3/4 stuff which none of us have played with, and even so, I've the sense that the planet in particular may be a bit too abstracted by the game mechanics currently.
So when Arcen returns to SBR, this is what I think needs to happen, and it's a straightforward thing - complete and begin testing the second half of the game (interactions with and obstacles caused by AI races/planet/events) so those system can be evolved into what the box description says they should be doing. At which point, the parts of SBR currently in place can be balanced against those challenges rather than us making wild speculations based on the present game experience.
This would also mean we should stop nitpicking and banging on about the economy until such concerns have something to be tuned to and balanced against.