Hi, the bend modifier is just an easy trick to animate objects, but you can use other more complex techniques.
I don't know if it's same tutorial you saw, but i suggest you take a look to our Animating in Forest Pack tutorial
. It describes multiple animation methods.
This link also may be useful. It's a evolution of the bend effect, to simulate wind on trees: http://www.ramyhanna.com/2011/09/blow-trees-blow.html
Another thought I've had is to animate the rotation in the FP Transform section? Would that work ok or do you think there will be any issues doing that?
Yes, there are not problems to animate rotation parameters, but please note that rotation will be the same for all items. To create a more plausible effect, you would use a Rotation map
, for example with a Noise texture.