While I think total touch screen is nice, there are many disadvantages for me:
-don't want to share my iPhone and all of its data with guests who come over and may want to watch tv while either I'm there, or off in another room. All of my texts, email, Facebook account, financial data, etc, is there and don't want curious eyes to see it or perhaps see an incoming text for example. I also passcode lock which leads me to the next issue.
-to just change the volume, fast forward, bring up the guide I'd have to: look down at iPhone, swipe, enter passcode, find app, open app, then look at screen while performing the function. All that even just to mute the tv if a call comes in. Oh wait, I can't because I'd be using my iPhone to take the call! Too many steps to do basic functions. With a harmony one I just pick it up and hit mute. Done.
I think the only way this could work would be on an iPod touch that is your dedicated remote. No personal accounts on it so you don't have to worry about all your personal data for anyone to possibly see, and you don't need to passcode lock it. You still have to go through a few steps to perform simple actions though.http://www.voomote.tv/en/voomotezapper/features/