Basically that it. I did have a hard drive connected to my 8GB Wii U Because I needed it to download ALL of the demos. But after deleting a couple demos after purchasing games, I ended up just sticking with internal memory. I did end up purchasing a 16GB tiny USB flash drive to hold future "WiiWare and Virtual Console games, but I don't think I'll get the disks when possible.
I heavily considered getting games like NintendoLand, Scribblenaughts, Sonic, etc as downloads; but Nintendo's license transfer policy (or lack thereof) was a big concern. I do find that sometimes I don't bother playing a game because that means I have to get off of the couch to insert the disk (holy carp I'm lazy), but so far that's the only downfall I found.
What about you guys? are you finding you need external storage? do you get disks or downloads?