A stereo mic is OK and all, but what happens if the camera is 20 feet way and you are shooting in a noisy environment? A lavaliere would be a lot more useful. If there is not place to clip that mic on, or you are in a rush to catch a shot (and have a person using a boom), a cabled shotgun mic would be useful.... there is more, but you get the idea.

The VMC-K100 adapter is just that - and it will allow you to connect your mic (or mics) of choice to your camera. To your point: "The VMC-K100 offers alot more options, but alot more work." - video is only a ortion of the entire equation. Audio can play a big role - as does lighting, and editing and the story...

I would suggest the VMC-K100 along with an XLR adapter (like one from BeachTek). And your investment in mics would be pro-grade which use XLR connectors.