I think you're misreading what the gift actually is.
The way in which the information is given, by giving it to 12 different superpowers; strongly suggests that the aliens are coaxing humans to unite rather than divide themselves.
The foresight is also not the main part of the gift, it is a consequence. The main focus of the gift is understanding the cyclic nature of things.
The gift ensures that humanity will have a different future (compared to when they didn't have the gift), and in 3000 years humanity will have achieved something that is of use to the aliens.
This is like watering a sapling. I water the sapling today, so that I may have apples from the (future) tree.
If everyone can see the future, then everyone will see what they are going to do. With the knowledge they might decide to do something different, and what they decide might prompt someone else involved to do something different.
The point of the gift is not to divine the future. Today, such a skill would be invaluable, because you would be omniscient compared to everyone else. But when everyone can do it, it's no longer a valuable skill. So you are right that it devalues the ability of foresight.
But the point of having foresight is not being able to tell the truth, but rather understanding the consequences of your actions.
It is never explicitly addressed in the movie explicitly, but there are strong suggestions that humanity is flawed, and does not understand that they are flawed (and why their decisions lead to bad consequences). One example of this is the trigger-happy nature of some nations, and the nationalistic attitude they employ to shut out other nations.
But with the gift of foresight, humans are able to understand that a decision they make today may lead to an unwanted (and possibly unexpected) consequence in the future.
For example, anyone who wants to either start or stop a global war can now understand the consequences of their decision before they make it, and thus ensure that they pick the best available option.
When everyone always makes the best decision that they can make, humanity will obviously flourish as a consequence. No one wants to kill. Everyone wants to survive, and they sometimes see killing as a necessary evil to ensure their own survival. But with foresight, they can learn to understand that violent self-preservation does not always achieve the best outcome in the long run.
By giving humans foresight, humans are now given the tools to make truly informed decisions rather than short-sighted decisions that are either misguided or intentionally sacrifice the long term for the short term. This directly causes humanity to advance in a way that it otherwise wouldn't. And this advancement is what the aliens need for the humans to reach their required potential 3000 years from now.
