[BlueTemplar]

It could slow down the expansion rates a little bit, but 1000 minerals/turn instead of 500/turn for a construction Yard won't make that much of a change.
(= still better than now?)

It will make a change after that though, when you build up the insfrastructure on your planets, satellites, weapon platforms and troops. So it should slow down the build up a little bit.
(= GOOD?)

I think it will help extensive empires a little bit, because the area (=productive planets) grows faster than radius (=system to put defenses into), and stationnary defenses will be more expensive.
(= BAD?)

It should help momentum (agressive) empires a little bit, since stationnary defenses will be more expensive to mantain.
(= GOOD?)

Also fighters will be more costly to maintain.
(= GOOD?)

Ressource bonuses and techs, reduced maintenance will become more important.
(= GOOD?)

I fear it will make the mineral planets more important, thus expansion could become even more important!
(= VERY BAD!)