IMO amps haven't changed at all since 2000, with the exception of some new tricks to increase efficiency and a few bells and whistles. That said I believe amps will continue to add useless features and push the efficiency envelope. I think the only great achievement we'll see in the next 5 years are mainstream (At least mass produced and affordable) amplifiers that push the 99% efficiency mark.
"Bunny ears" bolt towers (think Frankenstein movies), mini lightning orbs, cheapass oscilloscopes, dancing LEDs, LCD monitors, and just about any other visually appealing electrical appliance will find their ways into amps at some point or another. I'm waiting for the Mercury cooled amps that will circulate liquid mercury under clear covers in the amp's heatsink making it look like a fountain.