A Bayliner 2858 Cammander Bridge equipped wih a single engine OMC 460 seem
to be a good choice for my needs.

Is it funny to drive a flying bridge ?

....I find that a Flying bridge gives you a MUCH better view all-around and that
it's actually easier to pilot from there vs a lower bridge. The single engine,
28ft Bayliner you mention might be a little harder to manuever in windy/current
docking conditions, flybridge or not.... the bridge WILL have more of a 'sail'
effect in windy conditions.

A single engine is it enough for a 28th feet ?

....See above, but power-wise, yes.

caracteristic when it's windy.

....See above...