It is thread jacking, yes Find MapSizeDefs in the data/game folder, then change every instance of <MaxHabitablePlanets></MaxHabitablePlanets> to 999999. This should remove the arbitrary cap and you should get more planets.

I don't really agree, and there's a couple of reasons why:

First up, we have the simple fact that every point of movement is better for the player than the AI, due to the AI only ever attacking once per turn with any given fleet. This alone is, in my opinion, enough to justify capping speed somewhere around 20, simply to prevent the player jumping into a staging area, wiping out 5-6 fleets, and then fleeing to safety. Until the AI can do that too, very high movement rates are simply a buff to the player.

But above and beyond that, being able to strategically redeploy your whole military from one end of the empire to the other in a matter of 5 turns makes it near impossible to be caught off-guard. At 40 moves per turn, I can almost certainly bring my entire fleet to bear on any point in an astonishingly short amount of time. There's no line of supply; and no risk of strategic over-extension. There's no reason to use the movement-increasing modules on MSBs and fleet units. Making the player too mobile is almost as bad as making him not mobile enough.

Now, what I'd propose is this:

1) We base engines around a decently-armed ship having a top speed of about 20 moves per turn. Note that there's no hard cap - but going over this will require using more than 50% of hull space as engines, and so will be severely detrimental to the ship's armament and defenses. If you want a rapid-response unit, then by all means design them with 70, 80% engine; but you will not be able to go toe-to-toe with a fully-armed normal ship.

2) I buff the MSB movement boosters to halve the move price of tiles within AOE.  This means that, provided you spend some effort on the infrastructure, you can rapidly redeploy within your own territory, but will not have this bonus map-wide.

3) I buff the fleet movement-booster on ships to give +50% movement, but make it massive (like 1 per ship with engines and not much else). It will be vulnerable, particularly to enemy missile fire.

If you want to zip from one end of the galaxy to the other, then that's fine - but you're not doing it inherently with a huge warship loaded with weapons. That's poor design, as it cuts back on strategy. 

RE - Terraforming - Turn 400+ of a game and I still cant discern if the AI is terraforming it's planets. I can see about half the galaxy, and have eyes on 2 of the 4 most advanced empires other than my own. Neither of those two have done any discernible amount of terraforming whatsoever. I have about a dozen class 50+ planets, and the bulk are class 40 ish with the AI still rocking class 7-20 planets.

I don't remember this being a problem in earlier versions, but I'll have to check some save files to be sure. Regardless of any que or research issues you'd think if they have the ability to terraform they would have done it by now. The 2 powers I mentioned are pretty close in tech to me. If I wasn't fully terraformed (bioshpheres) they'd be beating me, but I'm starting to pull way ahead now.

I've annexed about two dozen planets from lesser AI powers, and most of them had not even begun the most basic terraforming projects (planetary soil upgrade) but a few probably might have (it can be hard to tell if there are just no tiles available or if the AI had done it). For the most part the 2nd tier terraforming slots were always available on worlds I'd taken from the AI.

But this is the case no matter if I have 20 speed or 80 speed.  And I know in CG2 the AI could and did attack with the same fleet more than once.  Not sure if this happened in CG3 yet or not.

So even with a speed of 20 I can still take out 5 fleets just as well as I could with 40 speed.  You nerfed sensors so that means I still have to find the enemy fleets.  Finally, one major reason for doing this is if you stack a single ship in the same hex as a fleet you don't attack all at once.  They are two separate attacks.  And the AI loves to have 20 individual ships in one hex instead of making a nice fleet.

As for SB's being something to defend not sure why something many times the size of a single ship would be weaker than a single ship.  Even in CG2 this was always strange to me.  A ship can fit inside a SB and be repaired but can't hold as many weapons or take as much damage before being destroyed.  In all honesty this is why most players (or at least me) never build them except for mining or to buff planets.

There's a big difference between your giant main battlefield being able to attack 20 times and being able to attack 40 times. Combat is too easy, and a major reason for that is being able to use 1 all-conquering fleet to move between a dozen targets and engage them in a single turn. Slower units will force you to spread your forces more, and helps to compensate for the AI failing to fleet up. 20 moves a turn is probably still too generous tbh.

Naselus, do you have any control how the AI views military power? It's such a big deal in diplomacy, and I really don't understand how the AI determines I am ripe for conquest. Late game its not such an issue, but I always find that even if I'm the toughest kid on the block the AI thinks i'm weakest.

They must be calculating something in their score that doesn't make sense. I read in another thread that they counted shipyards towards their military power, and since the AI and the player use this system in a fundamentally different way (players groups planets together for one powerful shipyard, AI builds one in each system). Not sure if this is still the case?

This is based on the false assumption that there are even 20 targets close by to each other.  The AI won't have 20 fleets.  It may have 20 individual ships but then that is the same as attacking a single large fleet.

Right now in a game on immense map turn 90 my empire is over 100 moves wide.  And I only have about 24 colonies at this time.  We will have to agree to disagree.  And I'll just have to change back the speed increases for the techs and engines.  The perfect solution would be for SD to add a multiplier to speed and engines based on map size and place this variable in a file where we could change it.

Yet on the small to medium maps I can move my ships in 1-2 turns max.  So it happens right now.  What we disagree on is if this should be the case for very large maps.  To me it is boring waiting 20 turns for a ship to get anywhere.  I currently have speed 17 ships on an immense map turn 90 or so.  I have only one small corner of the map and it already takes 5 turns to get anywhere.  My older ships with 6 or 7 movement are now garrison type ships.

Plus this really hurts the AI even more.  Not to mention the empires in the middle of the map.  I have a very strong suspicion that the AI will not move ships around the map if it exceeds too many turns.  That is probably why they build so many shipyards.

I understand what you want to achieve.

I have a different question.  In the change log you have "Culture buildings now add small ideology point-per-turn multiplier effect."  What ideology does this impact if I unlocked stuff in two ideologies?

would you port this change please.  Even though its faction wide, it could be made VERY small and give me a reason to build culture improvements.  Does it stack with every addition culture building?

Thanks,  I am putting this in my list of thing to maybe do later

Yeah, the game is incredibly challenging for quite some time (I play on the slowest setting so the challenging time is longer). I've started a new game where I'm playing house rules without any terraforming past the 3rd project (the furthest I've seen available to the AI, though I don't think they even use that). I play on incredible as well.

The later terraforming projects are a pretty nuts anyhow, class 60 worlds are somewhat common. Unlikely the AI will be able to keep up even with it's bonuses.

I am confused, as fighters do not use engines, how would tweaking engines through out the balance?