Function keys are trivial. I already have 1 through 0, and two more keys on the same row, so I map them to Layer 1, which I have both a momentary and toggle version of on my deck. I put F11 to the left and F12 to the right, not that it matters.
So for just F5, it's as easy to type as %. For, say, Ctrl-Alt-F4, I hit layer, then Ctrl-Alt-4, then layer again.
I grant that someone might make much heavier use of function keys and find this inconvenient. I don't miss them in the slightest.
An integrated trackball might be nice, although I'm not sure where to put it that would be comfortable. I have a trackball to the right of the keyboard, this suits me fine.
So for just F5, it's as easy to type as %. For, say, Ctrl-Alt-F4, I hit layer, then Ctrl-Alt-4, then layer again.
I grant that someone might make much heavier use of function keys and find this inconvenient. I don't miss them in the slightest.
An integrated trackball might be nice, although I'm not sure where to put it that would be comfortable. I have a trackball to the right of the keyboard, this suits me fine.