What idea/field in electronics is revolutionary nowadays
Not wishing to cover ground mentioned by Matt (although this may be difficult), medical electronics leading to greater body part replacements could be considered. Matt mentioned nanoelectronics and this, I'm sure wil play a big role. Tapping into the brain would be a massive (and probably quite dangerous but rewarding) enterprise. "We're all gonna end up like the Borg" maybe I heard someone shout via my bionic ears. Keeping mother earth up to speed with ozone production - maybe brainstorm how electronics can work here? I'm not saying it can; but I don't think anyone can say it can't - revolutionary new electronic developments may be brought about.

But, is electronics now just a means to an end - telephony and radio can't exist without electronics but did your average victorian ever concern themselves that writing letters would become a thing of the past. How many would have predicted the commuications avalanche we have today. Has electronics had it's day - In terms of functionality and performance for "non-grunt" solutions, electronics wipes the floor with "mechanics" and, of course, in many applications, software wipes the floor with electronics.

But, where does electronics still stand head-and-shoulders above software - maybe this will point to where electronics may continue to be revolutionary?