It _could_ be good yes. It could be just another way to input commands alongside with buttons and the analog stick. Doing all that in an ergonomic fashion isn't easy though as evidenced by all the solutions thus far.
Just a nitpick but the problem with your additional cost example is that there are already plenty of games that use motion controls that still require additional gear for that 'immersion' effect. Guitar Hero and Rock Band are not going to be use the Wiimote or SONY Arc or Natal effectively. Or anyone who uses the 'real' equipment will blow them away.
@killeryoshis,
I have to say I disagree with the notion that the pointer trumps the controller in all cases. Fact is, keyboard shortcuts are faster than the mouse and the d-pad/analog is more accurate and stable than the wiimote.
A warrior keeps death on the mind from the moment of their first breath to the moment of their last.
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