I do not see how "Spring as platform for many games" is like Unity, because Unity is excactly not like that.I think we shouldnt try to emulate unity.
Spring is not unity.
One Unity game has nothing in common with another Unity game, except being made on same engine.
But Spring games are multiplayer and so need an infrastructure of download systems, lobby, server, and playerbase too.
Comparing Spring and Unity seems like strawman.
Games are made of art and textfiles, that is how it goes. Get better at modeling/scripting/whatever and you find ways to be faster. The point is...?The reason is that making and balancing a RTS compared to other titles, is a huge timesink.
Overcoming these timesinks, that would be awesome.