Gimmick, a definition
I think its hard to argue that the wiimote is not, and will not, be used as a gimmick. That doesn't mean it suddenly ceases to be an important introduction to home gaming. My concern is that the predominate presence of the system's 'gimmick' will detract from third parties introducing more standard games. As Eusis has said about Twilight Princess and the sword swinging function; there is no neccessity for it to be included what so ever, as it does nothing to improve, and in some ways detracts, from the functionality of pressing a button to make Link swing his sword.
Although I don't argue that they may have initially appeared as gimmicks, the introduction of the mouse and GUI have their places because for many users they make it possible for them to use a computer for their needs. The hand held controller, what I assume is being referred to as a d-pad, is justified in its introduction purely from a prespective of gamer health.
The use of the Wiimote can arguably be discussed in the same vein; "Childhood obesity on the rise? Combat it with Wii!" The concept and very principle of this angle may seem ridiculous to some, but i'm sure others will see it as justifcation to buy a Wii over other consoles. However, the Wiimote at present seem to lack the vital component or reason for being that the d-pad, mouse and GUI all have and had going for them; increased efficiency.
As far as i'm concerned, the Wiimote's functions are at this point in time nothing more than a gimmick. There is a chance however, that it may become much more than that; motion sensing gaming could have an integral place in future console generations and gaming as a whole. But personally, I don't see that place justifying such features being built into the controller, and every game that uses it, just yet.