What I remember people complaining about in the 90s was that UIs were unstable and it was really hard to get X set up at all. Any complaints they had about UI design were muffled by the tears of joy they shed when they finally saw the black X on the screen instead of junk and patterns. But in all seriousness, I'm not against innovation at all. I'd just like to hear about some innovation aimed at existing Linux users rather than insisting that the users who
really matter are the casual, non-techie users necessary for mainstream desktop adoption.
Targeting "casual" users has resulted in some valuable work such as better stability and completeness in many programs, simpler configuration interfaces for many things (such as wireless configuration GUIs that were better than Windows'), and better support for multimedia. However (leaving aside the fact that those were all things that techie users were begging for anyway) there was a downside. Customizability and configuration options disappeared. People made assumptions about "normal" users that implicitly labeled a large chunk of the Linux community abnormal. Case in point: if you configured your wireless connection using NetworkManager and then switched to a different desktop environment, your wireless connection might not work anymore. That might sound like a bug, but it wasn't. It wasn't designed to work that way. How could that be considered remotely acceptable? Because normal people don't use alternative desktop environments. (Thankfully, I've since read that NetworkManager accepts plugins that write to the correct system configuration files, though I don't know if distros test and install them.)
And where's the payoff? What was the payoff supposed to be, anyway? Back in the nineties and early 2000s many people assumed Linux had to make it on the mainstream desktop in order to be successful, but I think we've put that that misconception behind us. Yet people still hold up the "casual user" as the gold standard that Linux is supposed to cater to, as if it were a moral imperative. Few Linux users fit that stereotype. It isn't that we're concretely knowledgeable about Linux. If you put ten randomly chosen Linux users in a room, chances are that for every component of a running Linux system there will be somebody in the room who is utterly unfamiliar with how it works or how to configure it. Obviously we should cater to ignorance, if only so we have the luxury of remaining ignorant ourselves. But there is a general savoir faire with computers that it is acceptable to assume. By savoir faire I mean whatever factor it is that explains why I am the person in my family who always gets a call on the phone when someone needs help with Windows 7. Even though I've never developed on Windows, haven't used Windows for anything more than e-mail, web browsing, and Office in ten years, even though I haven't used Windows personally in six months, even though I've never used Windows 7 or Vista at all. They still ask me for help with Windows 7, and usually I can help them.
All I'm saying is that it's acceptable for Linux UI designers to assume that the people using their UIs are likely to resemble current and past Linux users. Take a break from innovating for projected, postulated, hoped-for users. Innovate for the ones we already have instead.