Everyone is looking forward to improvements in the next generation, which are inevitable.
However, what specific elements of interactive entertainment will receive the biggest improvement is up for debate. The technical aspects are bound to get better, so we can probably expect better artificial intelligence, enhanced control, and ultra-realistic graphics.
But personally, I'm looking forward to a big quality increase in terms of writing. The scripts we've seen this generation have been pretty good, and they represent a huge step forward for the industry. After all, despite the obvious inherent flaws, games like Heavy Rain have shown us that video games can produce fantastic emotion, present moral conflict, and portray excellent character development. The only problem is that we still can't rival movies or books when we talk about story creation and development, but I don't believe we have to settle for mediocrity in that sphere.
I'm hoping it's inevitable that we see better and better writing as time goes on. Professional writers are being tapped every day and we've already seen some pretty damn good examples of engaging, well-presented plots and storylines. Of course, story is never the most popular aspect of any form of entertainment these days (sad but true), but I'm sure at least some developers will attempt to set new writing standards for gaming.