This is the difference of opinion, There are many things that can give people an advantage, but the opinion differs in that I for one class them all as boosting your skill artificially, just because the degree of boost is relatively small in comparison, it's still boosting your skill..
The difference with using a K+M against using a wheel or arcade stick is pretty obvious though imo.
With them you still have the same limits on your car or character. You can still only turn the wheels on the car from nothing to full lock for example.
With a pad in a FPSs you're limited to the speed you can turn by your sensitivity. You put the pad to turn fully and you've still got a finite amount of time it takes to turn.
Using an XIM this isn't a problem, you can maximise the sensitivity input on the console to something that would be completely unusable on a pad, then dial it down through the XIM. You can then beat this turning speed issue just by moving your arm faster or further.
I do think it's not a good thing, but it's inevitable, I know lots of very good PC FPS players that refuse to come over to the consoles because the PAD is so unfamiliar, they aren't prepared to spend months learning it to get back to the same level of proficiency they where at.
Good for them, I'm not sure why the whole of the console community should have to adapt because some ex-PC gamers are too lazy to adapt.
I can play equally well with a M+K and Pad, and it's no fuss to switch between them. But now if I want to play competitively with these players on the console, I have to move to my desk and spend $200 on an adapter to turn it back to an even playing field?
Assuming these aren't easy to ban/detect, then perhaps we've turned a corner, and developers should harass Sony/Microsoft to get M&K support in their games, at least that way they can balance things up a bit better, and people would be able to know easily if they other people are using a pad or mouse/keyboard and this would go someway to appeasing things?
As was said by Zensuji, these XIM devices have been developed to be undetectable.
If they've no reason to hide the fact that they're being used, why would they do it?
I'd have absolutely no problem with using a M+K on a console if it was supported, and lobbies and servers where segregated for pad players.
Until then, they only way I can possibly see the XIM devices are as cheating.