I think he'd be moderately proud of most revival era movies, seeing as they seem to return to the roots of what made his company legendary in the first place. Out of the revival era movies, I'm not sure... The Princess and the Frog is probably the one that best resembles the types of pelikula made in his lifetime, but that doesn't necessarily mean he'd be most proud of it. He'd probably be impressed with Frozen's popularity (though that's partly due to the good advertising and exposure it's had) and would likely be proud of how much their 3D animation has improved in kamakailan years (Wreck-It Ralph onwards, I think). Disney-Pixar pelikula have always been high quality for their time, but I think it's only recently where the Disney animation studios have really got to grips with CGI. And Walt was all for making his films revolutionary, so yeah, I definitely think he'd be proud of what his company can do with 3D animation nowadays!
I think he might be disappointed in some of the millennium era movies; as stated above, I really think their 3D animation has come a long way, and it's great quality now. But I can't say the same for Chicken Little or Meet the Robinsons. I always felt like the studio rushed into using 3D animation for a feature film before they were ready. In terms of TV shows, he might be disappointed at the lack of animated shows Disney has produced over the past 10-15 years, but fortunately that's starting to change and a few movie spin-off animated shows are currently in the works! So there's that.