If you want to split trunk into competing experiments (and eventually discard one) using a "traditional" RCS like Subversion, you can do that. Easily. Worrying about the linear history of rev numbers would be like worrying about the ordering of hash tags in git. Just ignore them -- you always can get the change history of the branch on which you're working.

The second example is a feature provided by distributed version-control, not the choice of "changes" over "revisions". It's maybe easier to implement distributed version control with the former paradigm, but it's not impossible in either case.

I spent years using CVS, then years using Subversion, now I have almost 2 years of git under my belt. There is something appealing about numbered versions, but there is no significant benefit over unique hashes of versions, or rather, any small benefits of sequential numbers is vastly outweighed by the tremendous benefits of unique hashes.

I don't think any developer would disagree that the ideal workflow is to do one thing after another sequentially. It's just that in the real world, reasons come up where you might need to create topic branches. Even if you rarely need that functionality, there's no reason to stick with a crippled system like subversion unless you really need the one feature that it's entire design philosophy optimizes (partial checkouts) more than solid fundamental changeset tracking and manipulation.

I'm no zealot—you won't catch me advocating linux vs mac, emacs vs vi, or ruby vs java. In most technology choices there is a wide range of tradeoffs and considerations. However Subversion is one of those rare cases where the tech is fundamentally flawed and serious developers need to move on, whether it be git, mercurial, darcs, or whatever. Subversion has a few use cases, and if you are not a professional developer then maybe it's deficiencies aren't very relevant. However, if you're slinging code all day, version control is your bread and butter, it will stay with you across languages and platforms, so it's insane to stick with a crippled platform that will always be that way due to fundamental design flaws.

I don't think so. I've been using git for about a year, and I still practically never branch or merge. Switching from task to task has a cognitive overhead that I prefer not to pay.