Unwise AI behaviour

I expect that if they did take class 1 planets, there'd be a load of people complaining about how stupid the AI are concentrating their resources on such worthless rocks...

In my experience, they *will* take class 1s. If there's nothing else left.
Why take a class 1 when there's a class 16 nearby? Or even a class 8 toxic. I'll take that over a bloody class 1, and the AI does the same.

This does not mean they won't; in one game where I made all my home system's planets habitable in the .xml, the smallest was a class 1 that I didn't bother with. Later on, some Korath idiot comes along and colonises it! Of course, it flips to me exactly one turn later. So yes, they'll take class 1s. Even when they really shouldn't.

Those people aren't very bright, frankly, those things end up class 16 in no time. At high tech levels they're among the best planets in the game.

Yeah, I had forgotten about the Class-1 in my game until quite late, and sent a colony ship to see what it'd do, and it turned out great! Granted, I had the super-duper-insta-terraforming galactic wonder, which helps, but even having to do it all "normally," it would've been a great planet that late in the game.

Maybe those people just don't know that the game excels at not making sense?   
You can't really judge people for not knowing something that clearly goes against common sense. It's not really a "feature", nor is it documented anywhere that it is so. So why that makes those people not bright, I wonder. Did you know that, the first time you played with this "feature"? Do you consider yourself a bright person?

At which point you don't really need them. And if you somehow do, it's easy as hell to culture flip them or invade.

As an aside, I just saw the Terran AI pass up a class 16 world to colonise a class 2. As in, the coloniser flew right past the class 16.
Maybe it thinks it's being a sneaky genius. I'll just point and laugh.

If you research to orbital teraforming first you REALLY get a boost out of those class 1-2 worlds because you won't have to build them they will all turn green !!

Yeah the AI is pretty retarded when it comes to planet colonization . They also ignore anomalies for a long time which is weird

In fact a class 1 planet is far superior to a, say, class 8 planet. This is because a low level planet benefits much more of the planet imroving techs.
Habitat imrpovement typically only frees up 1 tile on a class 8 planet while it frees up to 4 tiles on a class 1 planet.

In the end, after all the terraforing techs have been researched, a class 8 planet has turned into a class 11 planet while the class 1 planet may well have turned into a class 13 planet.

This of course makes no sence, and is an annoying bug AFAIK

Now, to be fair, the AI(s, there are several) is an EXTERMELY complex program, and it is making a large number of decisions. We can't see all of those decisions, and so "retarded" behavior isn't always a sign of inadequacy. That said, the program IS very complex. Anyone familiar with complexity will tell you that complex systems can develop quirky behavior under the most optimal circumstances.

Add to this that the AI has to be updated to deal with new variables every time new variables are added to the game. Ideally, an AI would be designed to consider variables in a modular way, such that changes to the parameters of the game wouldn't really affect it. It obviously does do this, witness the way it can use the ship designer, despite changes in the costs and sizes of various components. However, Dark Avatar significantly increased the dimensionality (if you will) of the space in which the AI has to deal with colonization. It now has to assess not only the current and future potential of a world and its environs, but also its own progress vis-a-vis colonization technologies, and presumeably an overall strategy for dealing with exotic worlds.

So, it may appear retarded, but that is just the result of sophisticated coding!

My opinion is that it's not really a bug, it's a question of investment. A class 1 planet may yield more usable tiles in the end, but you have to invest a sizable amount of time, money and research to get the full use, whereas class 8 or 10 or whatever only give you 1 or maybe 2 more tiles per transform, but you have more usable tiles right away, without the need for extra research or time or money. I don't think it's a bug at all. It lends itself some strategy really. Are you going to colonize a planet that you can't do much with for a while for the bigger payout at the end, or let the computer do the dirty work and terraform it for you, then take it over. Or will you colonize them and go neutral, so they're terraformed, but you miss out on other items you'd get if you were good/evil. I don't mind this at all really.

Well, when planets are defined by a stat such as PQ, what does PQ1 vs PQ8 tell you? Why classify planets with a single stat if that won't tell you much in the long run? Besides, the amount of time and research in both cases is the same, for partial/full transformation. And since planet pop doesn't really affect productivity, they're as good as any other - except for pop growth. So they don't make good econ planets. Of course, you can always ferry pop there.

Unless you are NEUTRAL, or have the automatic terraformer, in which case it will automatically update all the tiles when you land.

It's what we call a shake-n-bake colony...

When a "basically useless" PQ3 planet evolves into an excellent PQ18, you know something is wrong. And yep, with no cost as neutral, that's abuse. If they want to make more planets available (special environments, low PQ), then generate more "normal" planets, and use those others for some special feature.