I wouldn't say the board is too long either if your using for basically everything. If you wanted a pure park jibstick, then you could go smaller to say a 153, but at your weight/height I think a 156 is fine. Do you notice problems with your feet overhanging too far off the board? With size 12 feet, a 156 non-wide board might be too narrow for you, that's the only problem I can think of with that board.
BTW, the whole snowboard up to your chin thing is bullshit.
PowderHound and TreeNinja