WillC said:Sabi - I don't see the brown and wrinkled leaves that you mentioned. Is there much more to the Schefflera than what is in the photo?
Your Schefflera arboricola is tropical and is not likely to survive freezing temps. It does not require high humidity.
Outside it needs protection from direct sun. Light shade all day would be best. Indoors, it should be in front of a very sunny window.
You can safely prune it back to keep it at any size and shape that you prefer for as long as you want. There is no reason to prune the roots at this time. Pruning back stems does not have to be accompanied by pruning roots.