I didnt use the old FCP and im never going to use the new one, yet I dont understand the frustration that comes with a change in the user interface. Adobe, Autodesk, Microsoft and Apple all change the UI of their software now and then. This is why at the place I work we have Adobe CS2, CS3, CS4 and CS5 on every machine, I use CS4 while most of my colleagues use 3 and some use 5. In my case there aren't drastic changes between versions, but my point is that you dont have to conform just because new software is released.
To the pros: suck it up and install FCPX along side the old version if you intend to move on at some point. No one is forcing you to go into work the next day and use an all new program. You certainly lose money in the transition because things take longer while you are learning, but transitioning at your own pace makes things much easier. If you aren't a pro, it shouldn't matter much to you because you don't need to upgrade as fast and you wont lose money on trying to learn something new...
Ok, so you've never cut on on FCP before?
Right. 2 points to your statement.
1) It is not just changing the interface or UI. Its a change to how you edit. Its like PS coming along with CS6 and saying "That simple thing you used to do with importing your photos and resizing it, the way its always been done, well now you're going to have to relearn a new way we made for you" And you have to learn it, as the older version isn't supported anymore.
2) You could most definitely have to learn it or loose money. If you're freelance editor and you get a call for work on FC, but the post house is now using FCX, what then. Buy the system yourself, not go into work until you've taught yourself the newer programme?
Avid version 5 changed its Ui from its old versions, only slightly, but you didn't have to be re taught to edit to use it as it still used the same way of cutting thats been around for 25 odd years.