This has popped into my head just now as I see yet another classic game has released on Wii U.
Are we going to face another case with NX of Nintendo starting from scratch and re-re-re-releasing retro games in a spoonfed manner over the course of many years, with nothing to reward those that have bought the same game multiple times on previous hardware? Releasing the same game separately on Wii, 3DS and Wii U and expecting people to pay for it has been incredibly anti-consumer, even with a small discount for Wii U versions if you owned on Wii etc. (Sony isn't exempt from this completely, since it's not possible to simply transfer your classic PS1/PS2 games bought on PS3/Vita to PS4, but their case in the past has been to offer cross-buy so that if you buy on one system, you get it free on the other, and can transfer save files etc; and in the case of PS2 classics on PS4, they have been rebuilt to run on the system with small upgrades like full Trophy lists).
As the third home console since Virtual Console began, in my opinion at this point in time, it makes sense now to copy over every single retro game that is currently available on Wii U to be ready to go and purchasable on Day 1 when NX launches, with anyone that owns one of those titles on Wii U able to download the game on NX for free. I would say if you own a 3DS classic game that it should also be the case to get it free on NX, too, but I am sure a lot of these games have been separately built to run on each platform, and may result in two versions being on NX if copying straight over.
At the very least, use the emulation that exists on Wii U for NX to allow those classic games available now to run on it, and let users who own the Wii U version get the NX version free. We should not be starting from scratch all over again. Nintendo can set a precedent here. Maybe Nintendo will scrap retro game porting altogether, who knows. But if they are going to go ahead with it again, then it either needs to be the case above, or do what Sony is doing and updating each game they re-release with NX features, achievements, online play for multiplayer that was previously local only, etc. I would not buy Mario Tennis 64 again, but I would be inclined to if they added online play.