Simplification: the act of removing features that are deemed unnecessary, redundant, irrelevant. Simplification (UI design): the act of removing or transforming discoverable, one-step, procedures in opaque, 3-step-after-reconfiguration procedures. See Gnome, Windows, OSX. Hopefully not KDE.
Or perhaps, an alternative
Simplification is not so much about removing features, as it is about transforming user experience into something leaner. Simplification does not have to be a bad thing, it is all about how you do it. Simplification is really hard; it has to do with how a piece of software is structured, from the ground up. E.g. stuff that is not encoded into the data model, you will never be able to do in the UI. If you have a data model that does not fit the problem, the UI will never be a good one. You cannot simplify an UI just by rearranging icons. Well, you can rearrange, but it does not necessarily get any simpler - you are only giving it a minimalistic appearance, which "fakes" simplicity.
I organize my kitchen on a Huffman-style principle. The stuff which needs to get accessed more often, is more accessible. Why should a UI be any different. You want the stuff you need more often to be readily available, thus minimizing the total number of user actions. That does not mean you cannot have layers of functionality, or possibly alternative UIs (click to enable/disable wizard menu mode).
"Power tech users" are doing themselves and communities a disservice by inisisting on cumbersome, archaic, complex UIs in order to be able to fully wield their power in the UI they know already. Why? Because it hurts general adoption, which hurts software usage, which makes it less attractive as a software ecosystem, which gives it a competitive disadvantage vis a vis other platforms. You want lots of users, so the platform can live on for years and years.
Don't misunderstand me here; I hate ribbons as much as the next guy, and after I recently had to try out Office365, that interface had me going absolutely bonkers, having to send off an angry user feedback in order to vent.
I consider myself a power user, but tech is not my day job, and I am getting old enough that I no longer wish to spend evenings sitting in a basement learning the ins and outs of every piece of program I come across. I spent years creating complex high tech infrastructure setups at home, only to change it all into something simpler because I cannot be bothered to maintain it anymore when it breaks. Life is too short, and even as a "power user", you may not want to have to be an expert on everything. These days, I will choose the program which just works without having to spend too much time figuring it out.