Being only 16, I hope that my views will have some impact in this conversation... just some of my observations and thoughts... Folding knives will be popular. Everything is becoming more and more convenient. People will want a knife that is easy to carry around, and possibly conceal from freaking out the other people. However, if criminals begin mugging people more and more, hefty tactical fixed blades would be nice to carry around (next to the 9mm, of course).
There is also a shift toward everything becoming either "retro" or "futuristic". This may or may not impact knives, but retro/classic cars are still becoming popular, along with retro style furniture. Stainless steel appliances still seem to be on the rise in popularity. Curved shapes are common in futuristic designs. There are also many dual purpose things now, so multitools may become more popular.
I, personally, am a huge fan of linerlock knives. I'd love to see them continue in the next few years, or until a different locking mechanism comes out.
But, knives are still knives. Been around since rocks could be sharp, changed materials, but the basic function has not changed. It cuts. I don't see much changing, other than the convenience of folding knives picking up.