Adjacencies aren't useful if you can't use them.  Or am I missing something?

Hey, let's build a capitol at the most isolated location on the planet.  Because expansion isn't the reason we came here.

That totally should be part of the lore! 

After weeks or months on a colony ship the colonists throw a big party on the new found planet. At midnight the guy who is the most wasted is given a big dose of meth by the ships captain. Than the guy is blindfolded, spinned around ten times and finally he throws the ritualistic, golden dart at the planet map to determine the location of the capitol.

.... usually it takes several repeats in order to hit the map, poking out a couple of eyes in the process.

It's an old, spacefaring tradition!

Many good points already posted. Perhaps if colony capitals were required to touch at least two tiles, AND that the player could change the capital location after viewing what was first offered, we could have our cake and eat it too. For those who don't want to have more work to do, they could just go with the location as given. With the must touch 2 tiles rule, at least the capital wouldn't be isolated. But for those of us like me who would probably see a better location, I can move the capital from its initial location to one I prefer. This avoids the AI having to be taught to pick ideal capital locations, as the AI would just use the given location (which would touch at least two tiles). Of course this proposal is synthesized from posts above.

Suggestion: You Get What You Pay For.  (And then you pay.)  Add a +mp cost to "finish" a Colony Capital.

• Colonization Event screen also has a Capital Placement choice, with the following choices:
• Prefab.  Random hex, but fully built.  (this is what we have now)
• Bad: Game engine picks a random hex for you.  (Or maybe it deliberately picks a "bad" hex?)
• Good: Your capital is instantly fully built.
• Tweak.  Change location by 1 hex.  Capital costs +24 mp (or so) to complete.  Rationale: You fired rockets sideways while descending
• Add a mini-map showing only a large hex of radius 1 (i.e. 7 hexes total).  You can accept the center hex for fully-built, or any adjacent hex for the mild extra +mp cost.
• Funny: Also add a short time limit, with the 7 hexes starting small and growing larger.  You're in free-fall!  Decide!
• Wacky: Late-game tech could enlarge your palette of choices, e.g. to radius-2 around the random hex.
• Choose.  You see the entire planet, totally empty.  You freely pick a hex.  Capital costs +60 mp.  (You spent that much time doing a survey.)
• Maybe a better Advanced Survey Module lets you choose this option for zero cost?  (i.e. this becomes your default)  Good: A mid-game use for survey ships!

Generally, we could make the Capital's extra +mp cost be proportional to the number of adjacencies and tile bonuses it gets.  The better you place it, the more you pay for the privilege.

I agree with peregrine23. If anything on one of my planets is going to be off on a tile all by itself, I would rather it be the Colony Capitol than just about anything else. Why? Because the colony capitol doesn't gain anything from being adjacent to anything, which means that it's more optimal for the colony capitol to occupy as few possible adjacencies as possible than it is for it to occupy as many possible adjacencies as possible. The only time it's really beneficial to stick things next to the colony capitol is when I'm not going to be building that many of those things anyways, or maybe if the colony capitol sits at the junction of a couple areas which make good clusters, and even then it's at best a negligible net benefit.

This.  I personally like my capitol being isolated, with maybe one or two tiles next to it at most.  Yes, it's nice to have tiles next to it in the beginning as a colony is getting up to speed.  But I'd much rather use my adjecent tiles on buildings that can take full advantage of them.

This will give problems, not because the idea is wrong but at the moment upgrading unique buildings is bugged. See [.72.2][Bug] Multiple Research Cloisters buildable

There are solutions but those would require changes to the xml structure. I gave an example of one such possible solution (which literary uses a capitol upgrade path as example) in the Building uniqueness and limits thread.

But back to the original topic of the thread:

The location of the capitol can be a pain in the "you know what". While i would like to be able to pick the location for the building, i would not like to be entirely free in its location. In my opinion the location should be select-able by the player, but with a constraint that the tile must match a certain terraforming level (<LandPercentageMin> in the ImprovementDefs.xml file). This to reflect that when you make planet fall (in the real world) you do not pick a location that is just advantageous to the future colony, but also is limited by performing said planet fall successfully.

  I'd to be able to move / rebuild unmovable / singleton structures, like capitals, hospitals, and ideology buildings.

My bad for not being clearer.  I was agreeing with the OP.   A capital on an isolated tile cannot use its adjacencies, ergo, they are worthless.

and i think this debate wouldent actually be all that hard to solve

as long as the capital stays at +1 adjacency its subpar since adjacency bonus's are not used by the capital the fact that its +1 to all adjacencys is nice but not enough to overcome the fact that they are not returned

at +2 adjacency bonus it become even for any basic building bonus ( +2 one way = +1 both ways) again the plus to all is nice but surrounding it with different types of building now wastes the adjacencies those buildings create 

at +3 it actually becomes useful to place buildings next to it 

so to paraphrase this 

keeping the adjacency bonus as is = isolate the capital 

+2 indifferent to position 

+3 put it as central as can be

   Not sure I understand this.  Growth is population, so placing a hospital next to a capital gives you a +1 (+5%) to growth.  I am looking at a planet with a 2 farms and a fertility clinic next to a capital, and the clinic is level 3 - 1 from each farm and 1 from capital, for +15% growth.