Yes, Google has removed the feature to roll back to the previous version. Whenever Google Changes it user-interface (for any of its services), it's in a testing phase and the users are allowed to switch back to the old one and also give comments on the new one. This is just to see if there are a sufficient number of users who are finding the new-interface comfortable and also so that if there happens to be any bug in the new interface, the users can easily roll back and continue with their work.
After the testing phase is over, and google is sure that there are no bugs in the new interface and that the majority of the users are happy with it, the option of the old interface vanishes.
This has happened several times in GMail.
Does Google Drive sync with Local Folders? e.g. I have a folder called work (c:/work). I drag that folder to Google Drive Desktop, it syncs. Thereafter I create a new file in (c:/work). Will Google Drive sync that new file, or must I drag it into Google Drive Folder manually.
Not in that way. The desktop portion of Google Drive works essentially the same way as Dropbox: There is a special folder (usually called "Google Drive") in your file system. Whatever you add to that is synced with Google Drive. Whatever you remove from there is removed from Google Drive and no longer synced.
If somehow I lose all my files on Google Drive Web. When I login to the Desktop Application, will it sync and remove all my files, or will it sync the files in the Desktop App back into the web account.
How would you "lose all your files"?
If you remove the files yourself via the web interface, then, yes, they'll be removed from your desktop file system (assuming your PC is running and the app can connect to the Internet). However, they should be in your "Trash" folder so you can recover them.
How else would you lose them via the web? If you lose access to your account then the desktop sync app won't be able to log in and sync your files, so they shouldn't be touched.
There's not really a "login" to the desktop app after you've set it up. It runs in the background and you don't really interact with it directly. (Again, very similar to how Dropbox works.)
Are there any other limitations as well as more efficient methods of using Google Drive for my work?
That's rather subjective and not really answerable. We don't know how you work.
You should have a look at Google Drive in the Help Center.
Best Answer
See this post from the official Google support site. It has a detailed explanation of how to setup offline access to Drive for your Chromebook.
Enabling Google Drive offline
Open Google Drive either by clicking the Drive icon or by going to drive.google.com while you are online.The sync process will begin automatically.
Look for a notification at the lower right corner of your screen to see how many of your documents have synced.Remember that you must have at least one saved document stored in Google Drive to use offline.
After Google Drive is finished syncing, you can access your documents offline. Any edits you make to documents while you are offline will be synced the next time you’re online.