You do get used to it, but I don't think it's ideal, esp. when you're tackling a row of half-a-dozen enemies, some requiring multiple hits. However, I haven't had the difficulty some people seem to have had with getting it recognised - it's just a matter of getting the timing right, hitting when the lock-on turns red and making a strong "push" motion.
The move that should have been mapped to a button (or tweaked a hell of a lot more than it is here) is the backstep. It just isn't recognised reliably until you rotate the controller almost a full 180, and even then for every few steps you take, the game tries to force you forward. IMO, removing the need for this or making it far, far more reliable would have been worth the dev time.
Generally, once you get Sonic tweaked and boosted the Wiimote works perfectly, and any lingering problems seem to be issues on Sega's side (though those bloody vines are baffling, as they seem to register any strong motion...)
Oh, and as a sidenote, I'm baffled how anyone could have trouble with Wii Boxing - the game is a blast, and while the controls take a little while to click, when they do it's great fun to nail combos and hooks to flatten an opponent
