I'd never thought about it like that, but you raise a good point. I watched it a couple months back, never gave it much consideration beyond what I wrote. If you view the main goal of the story as being trapped in 'loops', unable to break the cycle/etc... Then I could be way off base about the studio exec interference.
The whole kid/TK theme just seemed out of the blue. They could have done the same thing with the next Hitler type, absent the TK, and the story probably would have been stronger/more coherent. Like you mentioned, the kid was hardly sympathetic... The fact he had a power beyond any other human sort of took away the impact and made him more dangerous and more suited for a bullet in the head. No matter what, he's going to pose a risk.
I saw the TK as a way they could have an epic battle, blow some cash on CG. Like I said, the time travel should be enough for any story. If they didn't set out with time travel and the 'inner conflict'/battle between your past self and a future you as their primary plot device, but on 'Going back in time and killing baby Adolf/breaking out of an unending cycle', the story would have been 100x better keeping the kid but removing the telekinetic bit from the story.
So whether the kid was crucial to the story they wanted to tell or not, the TK ended up being a distraction that convoluted an already difficult premise. I'd actually argue that it harmed a film with the kid/future evil/break the loop more than a film without the kid in it at all... In other words - A film with the kid in it/future evil lost more adding the TK than a movie centered on the future self/time travel paradox that added both the kid and the TK. As nonsensical as those last two sentence are, hopefully I managed to get my meaning across.