Hi everybody,
since I (and a lot of others) am very unhappy with the current invasion mechanics I used my christmas vacation to play around a bit with InvasionStyleDefs.xml and fiddled with the numbers so that invasion is not so easy anymore (tested with conventional and information warfare; but the rest should go in the same direction).
I don't want to bother with creating an account on Nexus or something like that, so here is just the changed content of said file for everybody who is interested: