I recently completed a scientific win game with BrazilCIV, and some impressions I've had in past plays have come back, so I'd like to share them with the community so they might be considered as a suggestion.
First I would like to say that the scientific victory, with the space race ending in the colonization of Mars, became really, really interesting. I've completed a couple of games this way before, but it's always really cool to complete this tech race, There's a real fight to keep at the top of the tech tree by research (AmericaCIV and NetherlandsCIV are very quick to research), The need to use spying to steal techs and stay in the running, simulating the wide spy war that took place in the space race period of the cold war is pretty cool. But I still think that the large number of turns waiting for the spaceship to arrive could be reduced, because after you launch the spaceship you just keep clicking enter to go through the turns, I think it could be reduced from 16 turns to a few 4 turns.
Some wonder effects could have some modifications
Brooklin Bridge, wonder- As it is released in Tech Labor Unions, its effect of giving free leeves in all cities is a little weakened because usually the player will have already built the leeve building in all their cities because buildings that give increase in science/production are very attractive and placed as a priority, so when you finish the wonder, usually almost all your cities already have this building. Perhaps moving this wonder to another earlyer tech would be good.
Bletchey Park Wonder - Perhaps it would be better to replace +4 culture with +4 espionage, since it is a wonder about espionage and at this stage of the game espionage points obtained without having to remove science from 100% are worth gold.
CERN Research Complex wonder - this wonder gives free laboratories in all cities, but as the tech that releases the buiding laboratory is Electricity, which is much earlier in the tech tree, this is a wonder that the effect is harmed, because the player is certainly already built the laboratory bulding in almost all of his cities because it is a building that gives science which is the most valuable yeld. So maybe it would be interesting to change the effect of this wonder. Maybe something like +5% science production in the laboratories of all cities would be more interesting since you usually already have the building in almost all cities.
Large Hadron Collider wonder - As this wonder is released in the superconductor tech, which is almost at the end of the tech tree, the effect of +100% science production has almost no time available to be effectively used. So maybe we could replace its current effect with Give a free tech (or if it seems too overpower give only half of the tech beakers), or even the effect of increasing the science generated by Great scientists/engineers when used for bulb tech, so that these units would produce an amount of bequers that if used would almost research a tech in 1 turn.
Oriental Pearl Tower wonder - it gives +2 science for each population point in the city. Maybe change its effect to give +2 science for each point of population and specialist in the city (because in a city with many free specialists or settled specialists this additional effect would have a great increase in the strength of this wonder)