Hello,

I can not say for 'melee' types, but as an archer (close enough maybe?) I only need to do the following:
- Left click with mouse on target
- Hit '1' (to use normal arrow) or '#' (to use a weapon skill)

I stay in fight mode all the time (sometimes for hours) so is rarely an issue for me to have to worry about switching. Also I believe hitting '1' (to fire arrow) automatically puts me in fight mode if I was not.

Maybe it is different for melee, if so, sorry for not being able to be more help.