People need to understand that Direct X is just an API. It's not a "feature" that graphic cards come with. It's a series of tools that allow developers to interface with the underlying hardware. That's it! Any feature that Direct X (to be more specific, Direct X 11) allows, usually is already available through the GPU in the form of a shader. More likely than not, Shader 5.0.
Just because the Wii-U's GPU isn't a 5xxx or even a 6xxx Radeon GPU, doesn't mean that its' visuals aren't capable of matching what's on those cards. Realize that Direct X is an api and its very bloated and slow.
So, consoles are able to utilize more power out of an older card than what's available on any newer card on a pc. Why? Because console developers wouldn't need to use Microsoft's API to interface with the hardware. They actually have direct access to everything. That's a bit different than on a PC since people have different set ups on their systems. So, developers are forced to use Direct X. Consoles on the other hand? Not the case since they're all the same. Therefore, if a developer makes a game for one Xbox 360 (for example) that game will work for ALL Xbox 360s.
Now, with that out of the way, we should know that the Wii-U will be very powerful. However, what about the games? Nintendo first party games should be a given, but many gamers are left with a bad taste in their mouths from the original Wii. That's mostly due to bad 3rd party games and ports. Also, gamers were very particular about HD gaming. Wii lacked that.
3rd parties were just as guilty as the core market. They refused to take the Wii seriously. They didn't want to put their hard core games on the system. They figured they'd throw a ton of horrible party games and casual crap to make a quick buck. All of that crap failed to sell. So, when 3rd parties realized this, they just gave up. Capcom is one of those companies. Zack and Wiki flopped (and it was a good game) and they just gave up. Evidence of that was when they said Street Fighter IV couldn't be ported to the Wii... But then ported it to the 3DS (which makes little sense, so they obviously lied).
However, this time around, the Wii-U will be getting much better 3rd party support. So, I'm not too sure why a good chunk of the core crowd is so reluctant to give the Wii-U a chance. They immediately point to the PS4 or the Xbox 720... Although they currently don't exist yet.