I disagree, I think that would give an impression that his power was unfocused. Which would be counter to the lesson he was trying to teach.
Also, in AOTC Dooku was tearing things apart - in ESB Yoda simply was lifting the x-wing out of water. Maybe there could be added bubbling and churning to the water but shaking trees doesn't make much sense in my opinion.
As for debris from when Luke crashed INTO the swamp, I'd be all for that.