Like it was said before, it's the grapple beam I'd love to see manipulated in more ways, moving things with it, throwing things with it, as well as swinging! They could incorporate it into puzzles too!
In regards to beams I'd like to see a larger variety, I liked the original Prime beam variations, they should keep these and add a few more to spice things up (can't think of much to be honest haha)!