Of all affinity abilites right now, the scientist collective mind is probably the most impactful one. The ability to at any time convert all your cities money and industry into science at a 100% conversion rate allow scientist cultures to go through the tech tree in a very short amount of time and thus cause the game to end due having researched all required techs. No other affinity ability, passive or active have anywhere near that kind of impact upon the game. Screenshots below show just how impactful the collective mind abiilty can be in contemporary:

Producing about 100k science as the Swedes, tech tree was finished in just a few turns

Went from having 22 techs at turn 98 to completing the tech tree and get all 92 techs at turn 130 with Japanese

The scientist collective mind ability unlike most other affinity ability have no restrictions in its use, you can use it in any number of cities and it last for as long as you want. The only requirement is that once you use it you can't turn it off for 5 turns, but it don't have any cooldown and you can turn it on again.

The builder active ability is similar but I don't think it have the same impact upon the game as industry don't directly end the game in the way science do, sure there are the space race but those projects are not that expensive.

What I think should be changed with the scientist (and probably builder) active ability is these things:

• Limit it to one city
• Is active for 5 turns after which it is turned off
• 10 turns cooldown after it was turned off