hmm. . .I had everything in my game set to uncommon and got a nice distribution.

I used the default settings and it seemed perhaps slightly more sparse but quite playable.   Heh heh, I also noticed that the Altarians got a very sweet collection of nice planets!

Could be you just randomly got a bad map?  It does sound strange though.

The first game I tried had uncommon for habitable. I found 2 planets in the area reachable by my survey ship before colonizing any either of them. I restarted and set it to common and managed to get 5. That is the game I am in now. Haven't met anyone else to see how their distribution was. I was using tight clusters on a huge map.

I started a game last night with common habitable planets but I was trying the Yor and didn't micro my population enough and restarted with another game with the same settings.  The first game I had a really nice starting spot lots of habitable worlds and several really nice ones.  Starting position for that game was on the right side of the map.  The second game there were only 2 habitable planets in range of my scouts, I had to get to the edge of my survey range before I started seeing common habitable planets and that was with colonizing the farther of the 2 available planets I found early.  Starting position for the second game was the upper part of the left side.

I think this just emphasizes what Mormegil just said, its hard to optimize and balance map generation.  The planets are there but there tend to be areas with fewer planets and that can really slow you down if you get a bad starting position but if you really like a challenge its not that bad.

It was in that "corner" probably the worst possible starting position.

I have been running on a huge map.   The general area you get before you make first contact is critical, of course.   With settings on occ/occ   I started a game with no habitable planets in my area.   Then I cranked up to common planets, still occ habitable.

I got 28 stars and 39 planets (there were 2 systems with 4 planets)  in my starting area.   3 planets were habitable - 5 - 9 and 13.  Guess I need to go common/common.  The number of stars for this area is about what I would have expected (I was at the tail end of a  spiral galaxy).  I am not counting the home system here.

Yes, I understand this is a tweaking problem.   If I can point out something else dreadfully obvious, is that it's a very critical tweaking problem.   The default settings should give a 99 % chance of a  reasonably playable start (which I realize is subjective to everyone, but still).  To me a half dozen or so habitable planets in 30 stars is about right as near the minimum.   You have to hunt for them but they can be found.

In Beta 2 I thought the default settings were about right, I even from time to time got two habitable planets in one system.

Related issue:   I noted the frequency of asteroids, nebulae, and ores in my starting area.  There were 16 asteroid fields and 12 had ore.  10 nebulae, and 3 had ore. (default settings).   I think I remember one of the devs mentioning the amount of ore might be a bit of whack in this build.   The nebular/ore seems about right though.