UI changes are inevitable, even open source software introduces changes. For instance, Firefox 4 was recently released and its interface has been reduced to the address bar and tabs, and some buttons, no menus. For some this works out well. For me, I prefer the menus. No fear though, it can easily be changed back by right-clicking in the toolbar area and selecting "Menu bar" and voila! the menus are back. Firefox also allows you to switch the tabs to be below the address bar, similar to the older look, by right-clicking and deselect "Tabs on Top". This gives the user the choice, which is the way it should be. I figured it out within a minute after installing Firefox 4 the first time.
Recently the hot topic in open source software is the new Gnome 3.0 shell (Gnome Desktop Environment). It's been minimized as well. The minimize button is gone from windows, and there is a new application dock instead of perusing through menus to launch an application. But, the users also have a choice which is to switch it to "fallback mode" which brings back the Gnome 2.0 look and feel. Again, this gives the user a choice. There are still some things to be worked out in Gnome 3.0, but we'll get there. Gnome 2.0 is a highly configurable environment, which is one thing I have always loved about it. Hopefully the same thought will be put into 3.0.
Another topic is OpenOffice, which more closely relates to the MS Office. A ribbon-like interface is currently being tested, similar to MS Office. However, I suspect that there will also be a way to allow the user to switch back to classic menus, considering OpenOffice (or LibreOffice) is open source and community-driven.
It's been a few years since Microsoft came up and implemented the idea of the ribbon interface in its Office suite. Initially, it stirred up a lot of commotion. But after a while, the complaints settled down and we didn't hear as much about it. But still even today, I still ask myself, "was it really necessary?". And, the main question I ask is, "Why didn't Microsoft allow the end user to switch back to the old menu system?". I don't really have the answers to these questions. But my opinion is that the ribbon interface really didn't get us anything of value. It looks OK, but to me it's clunky and doesn't give the user a straight forward system to look for a function or operation like the old menu system & toolbar does even today. It also uses more realestate (screen space) for the same purpose of allowing the user to select a function. So what if the menu system has been around for decades. It works, does it not? I can understand that Microsoft wants to introduce new features to make new versions appealing for the market to go out and buy. But in my opinion Microsoft could have given a little back to the customer, by at least allowing them to disable the ribbon and enable the classic menus. Give the customer the choice, instead of forcing the customer to use what you think they should have.
What does Microsoft have to offer, if the customer wants classic menus in MS Office? Nothing that I know of. However, some third parties have written add-ins to bring back a panel on the ribbon which has a menu in it. To me, this is the same as putting on a bandage over the real problem, it's like a menu on top of the ribbon.
I've touched on this before, but many times I've seen proprietary software continue to push its customers to do what it wants, rather than leaving the door open so that the customers have a choice with usable options. This is where open source software excels, because it is community-driven. And there are debates about UI changes when dealing with open source. But debates are good, voices are heard, and things usually get done to appease the majority. In my opinion this is why we see so much more flexibility in open source software, rather than proprietary software which limits and controls the users.