There's no point in this because any Wii U game worth playing will be ported to the Switch in some form or other, and top Wii games like Galaxy 1+2 will most likely get the remastered treatment.  C'mon, you KNOW Galaxy 1+2 HD will be brought to the Switch at some point, as will LoZ TP &SS.

That would be cool if they could do that, but I figure that would need more effort than it's worth doing. It would probably be too difficult to do with Wii U games, since those worked with 2 screens in mind and may need to tweak every game to work with one. As for Wii games, it would probably come down to if the Switch Joycons would be compatible with them.

Even if that became a reality, I'd rather just keep my Wii and Wii U to play those games.

Honestly I would buy that. But to play Wii U games you would need to connect the Gamepad and that would be hard to achieve.

I'd just plug in my Wii U since it's BC with Wii and do it that way instead of buying an add on. Now, if they were just going to give it away to owners? That would be different.

Not going that happen for three major reasons. First, this would highly interfere with the whole, seamless switching concept. Second, you’d have to emulate Wii / U games, and Switch is not powerful enough to do this. Even if we see homebrew community getting to the point where they’ll be able to run custom hardware, for this reason alone it won’t happen. Third, it’d hit Nintendo’s software revenue.

Now, personally I think this would be great for enthusiasts, but like I said previously, from the technical point of view, you’d have to emulate the whole thing, there’s no way around it. And yes, Switch is more powerful than both of those systems, but I don’t think it’s powerful enough to emulate them (definitely not the Wii U). 

Well first up, it wouldn't work at all.
Switch isn't hardware backward compatible with Wii or Wii U.

And if we're talking about whether I'd buy some hypothetical magical gadget that could do something like this, there's a huge host of other gadgets I'd get before this one.

I'd prefer the ability to link a hard drive to the dock, and give downloadable access to the Wii library - and ports of Wii U games. Unfortunately, the Wii U library won't be compatible with the Switch without remaking due to the Gamepad; the Wii to Switch conversion would be much easier since it's already known how to turn a Joy con into a Wiimote.

While I would prefer a way to replay my digital purchases from the Wii/Wii U, a disc drive add on alone will not get it done. Most of the games would have to be retooled due to controller issues in order for them to be compatible.

I do hope they find a way to bridge the divide between those of us that purchased on the Wii/Wii U and also got the Switch so we aren't just rebuying the same software in a loop but there are way too many hurdles blocking it beyond just the software physical format.

A disc reader woukd be too much hassle in the eyes of the consumer. You woukd not be able to use it for portability, so whats the point?

Plus most people who have their WiiU games, still have a WiiU due to rarity. Not enough people would benefit from that to make it worthwhile. Hell I would even go as far to say that even the Wii owners still have their console if they kept their games. WiiU was the only console to upgrade to, and hardly anyone did it.

VC and WiiU remasters, believe it or not, would be far better than this kind of BC.  At keast this way there are no extra pieces and all games remain portable.  I am sure some of the Wii games would be the exception due to motion controls, but it would still be easier IMO.