Well, not sure if you really need it bigger or just want the illusion of it bigger.
Yes, the handrails too high will make it look like its fenced in and small.
Code in CT says 36" minimum. When the guys were building it, they were doing it at 42" which is standard but I saw none of the backyard so I said do 36". Amazing how much roomy it made the deck! But thats a lot of work. Cutting all the balusters, 4x4's, ect.
trims the shrubs around the deck.
How about replacing the floorboards and doing a diagnol design instead of straight? That will give the feeling of a bigger deck.