Ther currently is a problem for developping late colonies (either because you captured a badly developped planet, or because you colonize some planets late in the game just because the galaxy is so large...)

The problem is: at the beginning of the game, you begin with cheap factories ; then you seemlessly upgrade the tiles you chose until you reach the industrial sector.

That is well and good.

However, when you colonize a planet AND already know industrial sector, then your sole choice is to begin building industrial sectors, which will really take ages.

My suggestion is that you should:
- Always build the cheapest improvement on a tile (hence you don't get the choice for "industrial sector", but for factory) ; when it is completed, the upgrade should be automatically queued. In this way, the cheapest improvement would participate in the manufacturing power of the colony while reaching higher levels.
- Increase the base industrial (and research) values of the starting colony square ; for example, add +50% to it's value for any level in manufacturing/research you have. Thus, a late colony square could be producing it's base 10 plus an additional free 20 just from technology. Late colonies could thus become usable before the game is finished, and would not ba a drain to your race (currently, either you set your slider to social production and waste a lot with planets already filled up, or you buy the social improvement, which requires a quite healthy economy!).