- Cost wise, you may find the price difference to be a wash depending on what's important to you. 32 GB fills up quickly. I recently bought a 1 TB drive for extra space. As a whole when one includes the drive it costs the same as a PS4.
- Short battery life for the controller. You'll get about 5 hours of game time. As a result, you'll want to take breaks and dock it to let it recharge. Normally, this isn't a problem for me unless the wife is out of town for the weekend and I can seriously sink some time into a game. Then, you're cut short which is annoying
- Locks up - My Wii U has locked up on me more than the Xbox One or my PS4. Lock ups occur in both disk and download games. As a result, it's across the board and random. However, it tends to happen if I leave the console on and let the controller charge while I do something else. I can come back for a bit and play and then it will freeze up completely. There's plenty of air around it so over heating shouldn't be the culprit.
- IMHO, there's a Zelda game at the end of the life of a Nintendo console generation. I would almost expect this is the last major year for the Wii U with 2016 being the launch date in the spring for other Wii U games (Xenoblade X) with a 2016 "new" console/handheld coming in the fall. I think the Wii U bows out after 4 years and moves on to something else.
That con list is a bit idiosyncratic. My Wii U doesn't lock up, $100 is a ton of money to me and a lot of other people and HDD size is kind of "first-world problems" to me, 5 hours of game time is a luxury many of us here will never see (however, I think you are overestimating battery life there) and I very much doubt the Nintendo swan song game for Wii U is in 2016.
All they have to do to claim an acceptable 5 year life cycle is make it one more year, and all they have to do to do that is move two or three things on the slate now forward one year. When was the last core game from Nintendo for the Wii in North America? 2012. Xenoblade Chronicles. 6 years. The last Gamecube game? Twilight Princess. 2006. Five years. The last N64? Paper Mario. 2001. 5 years. Despite the Gamecube not being a huge seller, despite the N64 and Wii being dead in those respective years, Nintendo always does a swan song no sooner than 5 calendar years. They abandon systems quickly, but never that quickly. If you buy a Wii U now, the last first party exclusive to want will be 2017, with the "best" game coming either this year or next. With the indie market on there, the last interesting game to get excited about will probably be a year or two after that (as deficient as the service was, Retrocity Rampage came to Wiiware in 2013, unfortunately for its developer, even though the system launched in 2006).