The IR pointer is very accurate.
Some things that CAN be an issue if the gamer or developer let them, are the fact that it doesn't necessarily act 1:1 with your TV screen.... ie if you actually look down the length of your remote like a gun barrel it might not be pointing where the on-screen pointer is.
This is not actually a problem unless you are holding the remote up to your face all the time, and in fact makes it easier to use on small screens, where if it was direct pointing it would be too sensitive.
Games that need it to be direct like rail shooters generally have a calibration option to alter it.
The turn speed thing you mentioned is a game mechanic problem, and one I have reason to believe will be fixed with The Conduit from the info seen on the menus.
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The only actual problem with it is that is is affected by other IR light points.... so if the sun reflects off the corner of something shiny toward the Wii remote it can register as a new point of light, which can make the pointer jump across the screen... again this isn't much of a problem and just involves you either not having things that can reflect a point of light below you TV (the 'point of' bit being important) or closing the curtains of something similar.
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Oh yeah, and motion plus will have no effect on the pointer function, because the pointer is more accurate than M+ (it needs to be)
