My biggest problem with the setting terminology is it's not relative. If Habitable Planets are set "Rare", and Extreme planets are set to "Abundant", then you end up with like a 1:1 ratio between the two.
To the poster that liked "Uncommon" in 5.1, then you should feel right at home on "Rare" on 5.2 for Habitable planets.
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Resources Spread Concerns
First, I don't really have a problem with the resource distribution being uneven, but it has other potential effects that should be considered.
Antimatter only spawns around blackholes, which makes it the rarest in most cases. If you add a ton of blackholes to the map you can increase it, but most people won't. Blackholes above "Occasional" is a bit silly looking.
Elerium spawns in/around Nebulae. And you did such a good job on making nebulae look great, that we want lots of nebulae(okay, I do). This makes Elurium a bit more common.
Durantium. Yeah...
These three are the main concern, as they will be the weapon related resources. If you were to not have any antimatter, then you may avoid missiles all together.
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A part of me likes that your empire is shaped by the available resources. It's a similar situation to strategic resources in many a Civ title(which were done well, imo).
The other part of me wonders what happens to a game of rock, paper, scissors...if say...you forget the scissors.
