Thin Your Client
If your UC&C implementation comes with a 400-page user guide, you've got too much going on.
Using an embedded Web client to glue people together in a UC&C implementation isn't a bad idea, especially at an enterprise with more than 10,000 endpoints. But you have to wonder how that's going to work when users receive a 400+ page user guide. This isn't made up!
One idea I will toss out is that the company needs to provide every user two desktop monitors. One would be for everyday Windows functions and apps, and the other dedicated to the UC&C client with its endless advanced productivity-enhancing features, such as what time of day and days of the week to route calls to cell or home phones or other destinations.
I continue to be amazed that any IT department would set itself up to have to educate users on so many features while still maintaining control over IT assets so that business isn't disrupted and users can do what they are charged to do each day. Perhaps specialized IT staff could interview the 10,000 users and develop a feature deployment plan based on factors like rank, pay grade, or serial number so that UC&C will be deemed successful. But not all users will respond in kind and loyally follow the regimentation.
Of course, not all UC&C deployments pan out this way, and those that do aren't only large enterprises.
Along with UC&C feature bloat, "call handling" is becoming a lost art. Communicating with one or more parties today can take many forms -- text, voice, video, IM, conferencing... and on bad technology days, pigeon post. If you need to toss in an advanced feature such as desktop sharing, and you simply add an icon (not to discount the talent that goes into programming and testing).
This brings me to my next point. What some users do see is bloat and again, not to over-generalize, but here are 10,000 examples that I've seen. Why? Why do users need an entire Web page to collaborate or make a phone call?
When opportunity knocks you either beckon to the call or you pick another battle. When someone insists that I use my browser to take advantage of all the super features that are going to make me more productive, and then hands me a 400+ page user manual on how to use this new tool, I can only wonder whether I'm also going to get issued two, three, or even four computer displays and then Firefox, Chrome, Edge, and Safari browsers to complement each one.