It depends on who you're asking. If you ask Wii U owners, not so much, since they've likely played any games considered for a port. Non Wii U owners, I definitely think so. It'd definitely allow them to play some of the best titles from the system without having to buy it.
As for the fear of there being more ports than new games, Nintendo's releasing a fair amount of new games as well, so there will be something to play for both new and existing owners.