Having to learn how to use powerful tools is absolutely fine when the tool is a specific one designed to be used by power users. For something like Wikipedia for whom the bulk of the audience visits briefly and occasionally to grab information, it's not a good thing. I think a lot of us are scarred by changes like these to our "power tools," which can be incredibly frustrating, but Wikipedia is a different beast.
Your design should fit your audience, and I think it's a good change to have a sidebar with tools that are surely ignored by the _overwhelming_ majority of users not be presented in a persistent, important ___location.
Also worth mentioning that they aren't removing anything, just altering presentation to better suit the common use case.
That seems obvious but it's not necessarily true. It seems to be an increasingly popular philosophy in this data-driven era of telemetry though, so I'd like to offer a counterpoint.
I want Wikipedia to be as convenient as possible for the editors/authors, even if most users are readers. The authors -- even as a small minority of users -- create the content that, in turn, attracts the readers.
It's possible that alienating authors to prioritize the reader experience ends up driving away readers through the second-order effect of driving away authors.
(I'm not saying that these particular Wikimedia changes are an example of this, just illustrating a mechanism by which prioritizing the experience of the majority of users can end up harming them in the long run, because second order effects are important too. Wikimedia seems to have thought carefully here, which is good).
An extreme example of this philosophy would be noticing that the vast majority of your users never touch the edit button, and so getting rid of it entirely to streamline the interface for everyone else.
'Editors' and 'readers' is not a binary dichotomy. One of the great things about Wikipedia is that anyone who happens to be reading an article and notices an error can correct it without much friction.
This is mostly only important insomuch as it helps recruit new editors. As a fraction of effort, those drive-by non-logged-in edits are a trivial contribution.
Your design should fit your audience, and I think it's a good change to have a sidebar with tools that are surely ignored by the _overwhelming_ majority of users not be presented in a persistent, important ___location.
Also worth mentioning that they aren't removing anything, just altering presentation to better suit the common use case.