Keep it free - and that includes TF2 style, mini transactions too.
I would like to see SD earn their money via association to the game - if it’s strong enough then you’ll benefit financially by proxy.
With such a method of operation you could change the entire face of current games development, which may also (hopefully) change how developers interact with gamers/consumers.
I can honestly say that above all else I’m hoping your intended model lives up to this expectation. That you repair the damage done by the greedy, under-developed tripe constantly spewed forth at regular intervals by IW et al. Whose sole focus appears to be maximum profit, often eternally at the expense of even a properly developed product upon release.
If Splash Damage return the gamer/developer relationship to one of balanced developer committment to gamer investment, then I’m sure gamers will continue to support them - I know I most certainly will.
It’s about time gamers weren’t simply perceived as a source of infinite cash by greedy halfwits, chasing a business model designed to deliberately target under-age gamers in order to mask professional incompetence and their own clear lack of imagination.
Good luck with the project. If I can assist, then please do contact me.