What's the problem?
One problem is that the reality can't catch up to the hype. There isn't much unified about UC. We don't have one inbox, because your cell phone accumulates text and MMS messages that don't make it into your email+voicemail box. In seems like the cell phone is becoming the inbox.
Most of the UC companies are more concerned with video conferencing or its elite brother, Tele-Presence. Yet the dollars just aren't there. And the same issue we had with IM/chat is befalling all IP Communications - Fax over IP, HD Voice, and Video Conferencing: Inter-Operability.
There isn't enough VoIP peering for FoIP and HD Voice to take off. And video conferencing vendors tend to make proprietary gear that can only talk to other gear from the same manufacturer. Raise the ocean people! Standardize on one platform for gear specs, inter-operability and transit.
Another problem is that UC is getting confused with Collaboration. How can SharePoint, Dropbox, HyperOffice, WebEx and video conferencing all fit in the same term? It's too much confusion for most businesses.
IT directors and business owners aren't even aware that these are pain points, because the message is cloudy (pun intended). Laptops and Macs are very different, but mostly interchangeable. WebEx and GoToMeeting are interchangeable. But UC or Collab are just too vague - and seem like too big a project to tackle.
UC is a sandbox full of toys to play with, as I said on the XO Tech Data UC Program Discussion. And as we saw at VoiceCon 2010 in Orlando, even people in our industry have different definitions. Plus again there are huge hurdles to fulfilling the dream of UC yet.
It isn't really about the buzz or whether the term is trending, it's whether the solution can be delivered to the customer.
A buddy of mine emailed me today that he was leaving his position at a cloud company because they couldn't deliver and the support was not up to par. That burns everyone - the company, the Industry, the salespeople.