Why do we need Ancient Ruins Modifier, Optical Scanner and Planet Stealth Modifier at all?
There is not technology in the tech tree for Colony Pod, Optical Scanner, Extra Fuel Tank, Ground Troop Pod, Defence Grid and Laser ship parts. (Or the starting hulls and buildings such as Basic Shipyard and Orbital Drydock)
If we must have the three starting techs, their effects could be combined into one starting tech, so be less cluttering.
Or, the ship parts mentioned above could be on the tech tree as pre-researched techs and the effect of Optical Scanner technology (for planets) could be added to the Optical Scanner ship part technology.
It seems strange to me that I must research Galactic Exploration even though I start the game knowing how to do starlane travel. It would make sence that all the knowledge that I am already using shouldn't need researching. The basic technology that everyone starts with should be on the tech tree, so that in the future there could be campaigns where you could start out not knowing some things. Also it would be desirable to be allowed to start an Empire which doesn't have all these technologies at the beginning of the game.
If all the technologies on the tree had prerequisites which everyone started with I think it would be a more elegant design.Colonies/Outposts
Also, colony ships are known at the start of the game, but outpost ships must be researched. This seems wrong to me. The game should start with the ability to put outposts on planets (which can research, not farm) and colonies should be added later with reseach. Asteroid Mining reseach should give the ability to put outposts on asteriods. The farming focus shouldn't be allowed on asteriods, just mining and research and later production (when the asteriod hulls have been reseached).Refinements
There are vast amounts of hulls on the tech tree, but not many ship parts. Maybe different sizes of hulls of the same basic type should be refinements. We have Basic Autolabs and Basic Autofactories, but no advanced versions. These should be refinements.
The refinements should probably have the prerequisite of a theory a few steps further along the tree, so they cannot be reseached right away. (I always research Greater Industrial Centres and Supreme Industrial Centres right after Industrial Centres, so I get a big bonus very soon after the starting smaller bonus.)
My final point - trees grow upwards. the tech tree in FreeOrion goes sideways. It is a tech creeper.