Nintendo has never been one to follow the competition instead opting to blaze their own path in everything from hardware design to the current digital download push. In a surprising turn, the eShop has been one of Nintendo's biggest success stories for the Wii U (and 3DS) with its low entry cost for developers, ease of use and high profit margin which makes it quite enticing for indie developers as well as one of the stealthiest (and more effective) entries into the digital market. Nintendo has taken one of the more reviled concepts of modern gaming (digital downloads) and made it both easy and inviting while not shoving it down our throats. This is what people refuse to understand about Nintendo, they don't operate like a bloated profit driven American company and they have survived (and thrived) for over 120 years! Their focus on fun and innovation over tech numbers and "trends" has made them unlike any other video game company and a true leader in the industry. The other thing to note is that Nintendo's conservative approach to hardware means that they have little to no loss on hardware cost (unlike their competition) meaning that they can easily afford to sell less hardware and make money on their software which sells in the millions even with a small install base. This strategy made the GameCube (Nintendo's lowest selling home console) a financial success despite being "beaten" by the PS2 and Xbox. Put simply, the Big N knows how to make money but that is not the driving force behind their games. When Shigeru Miyamoto or Eiji Aonuma design a game, they don't approach the design thinking how much money the game will make or what demographics it will appeal to, they focus on whether it will be fun to play and what kind of new ideas they can introduce.
All of this brings us back to the original question, "Is it really worth supporting third party's on Wii U?". It is really hard to defend some of these companies when they seemingly go out of their way to show their disdain for Nintendo. The argument could be made that Nintendo's previous hardware (N64, GameCube and Wii) was in such contrast to the competition that these companies were justified in their treatment of ports to those respective systems. This belief falls apart with the Wii U however as the hardware is the most mainstream since the Super Nintendo. Multiplatform indie titles made by small teams have had no problems with the hardware and have actually praised what Nintendo has created. Nintendo fans have been burned so many times by major third party's at this point that it is little surprise that their games don't sell to that audience.
Ultimately the answer is "it depends on the situation" but it would make more sense to look at each individual company. This list includes every major Wii U third party in the industry today, whether you should support them and a brief synopsis of why.
- Sega - (Should you support: Yes) Since going third party in 2001, Sega and Nintendo have had a great relationship. Sega has thrown a lot of support behind every Nintendo machine since this move and has been rewarded with great sales. Sonic has always done best on Nintendo machines and Sega has been responsible for bringing some of the better sleeper hits to the GameCube (Skies of Arcadia) and Wii (Madworld & The Condiut). Expect this relationship to grow on the Wii U as Nintendo will likely bring Sega closer to help support the console.
- Electronic Arts - (Should you support: No) EA has pissed all over Nintendo and its fans for years and has justifiably been shunned. Sales for their games have declined steadily since the N64 and the Wii U situation feels like the "straw that broke the camel's back" for many fans. With the exception of the excellent Need for Speed: Most Wanted U (which developer Criterion, not EA, was responsible for), EA's Wii U games were all lazy or inferior ports of the 360/PS3 versions.
- UbiSoft - (Should you support: Maybe) UbiSoft started out strong but recent decisions have put them on seriously shaky ground. The turning point will come in 2014 and it is likely that UbiSoft will drop a lot of support for Wii U (unless they see some major sales from their fall lineup). Rayman Legends is a must have for Wii U and despite some shaky reviews, ZombiU is a must for true survival horror fans.
- Warner Bros. Interactive - (Should you support: Maybe) This one really depends on your tastes, their family friendly games like Scribblenauts and the Lego series are great on Nintendo systems while they have made some questionable decisions with Batman: Arkham Origins and Injustice: Gods Among Us. Expect them to continue supporting the Wii U but they may focus more on their safer family friendly titles in the future.
- Capcom - (Should you support: Yes) While support is light, Capcom has actually been good to the Wii U. Resident Evil Revelations has the same features across all home consoles and even has some nice Wii U extras while Monster Hunter 3 Ultimate is exclusive and loaded with content and excellent online play. It's far more concerning when looking at Capcom as a whole, there is a very real possibility that they may not exist in a couple years due to a slew of stupid business decisions and turning their back on fans.
- Activision - (Should you support: Yes) Activision has been pretty good on Wii U support with a solid selection of games. Skylanders continues to do quite well on Nintendo systems (the Wii versions are by far the best selling games in the franchise). Call of Duty is also continuing to make its way to the Wii U and development studio Treyarch always impresses with its work on Nintendo machines. Much like UbiSoft, this situation could change dramatically in 2014 so stay tuned.
- Square Enix - (Should you support: No) Square Enix is struggling to regain its once great position but the core of the company has made some downright poisonous decisions. The Deus Ex situation shows this off in spectacular fashion. Being their first Wii U effort, it started as an exclusive with full integration of the GamePad to going multiplatform and charging $20 more for the Wii U version for no reason. The game may turn out great for the system but there is no excuse for this kind of customer treatment. Support at your own risk.
- Namco Bandai Games - (Should you support: Yes) They have a couple games on the Wii U and they are good games handled with care and this looks to hold true with their future releases. Namco's relationship with Nintendo is strong and they have even crafted a few of Nintendo's own games in the past so you can expect this to grow in the same way as the Sega relationship for Wii U. It should be noted that Namco Bandai is helping to develop the new Super Smash Bros. which will be a major system seller in 2014.
- Disney Interactive Studios - (Should you support: Yes) Disney likes Nintendo quite a bit and shows this with their software support. In all honesty, Nintendo has often been considered the Disney of video game companies so their relationship makes a lot of sense. It should be noted that while Disney owns Star Wars now, their decision to use EA as the exclusive developer of future games means that the Wii U is not likely to see any future Star Wars games.