The resource improvements were great when they introduced them but perhaps a little OP. As seems to be typical, they over-reacted to the shrieks of the power players and made them nearly useless. I am kidding about the power players part. I actually think it was changed due to a disagreement among the devs.
In it's original iteration, the Antimatter Plant gave you either a 4 or 5+ adjacency bonus to everything. Now I think it is +2 and nearly worthless.
The Promethium Pleasure Palace originally gave a +6 to base wealth and adjacency bonus to moral improvements. The wealth boost was probably an error but still made some sense and I really liked it.
Someone made a pretty nice mod that buffs them up. It can be found in the mod forum as Worthwhile Resource Improvements Mod.
It's great that the game can be changed if you don't like something, but at some point I hope they get the base game balanced to the point that mods will only deal with flavor and not playability.