Adding/Removing stuff is the whole purpose of the retrospective, the last feedback loop of scrum, feedback on the process itself. That should be the first thing you add and the last thing you remove.
"By-the-book" scrum is like applying all the GoF Patterns in your project. But yeah, I'm nitpicking, I know what you mean: I see around me plenty of positions for "Scrum master, good at removing impediments, x years line management experience, expert with Microsoft Project, no development experience necessary ..." and I'm thinking WTF ...
RUP is agile. You are not supposed to implement everything that's in it - even better, you are supposed to pick one stuff at a time if you face the specific problem the new stuff is supposed to solve.
Don't you really see a problem on describing a ton of rigid procedures, that only work well in concert, and expect people to "pick just the ones that are usefull, be reasonable"?
That is your problem right there.
7 years ago, scrum was taught as a toolbox. Each "procedure" had a goal. Reaching the goal mattered, not following a recipe like a lemming. It was for example perfectly reasonable to get rid of the daily standup in a 3 members team, if you have plenty of interaction with others already. The core of the methodology fitted in a single page.
All the above FYI only, no need to call the True Scotsman to the rescue, I'm convinced: from the other comments, scrum looks more like Prince2 than anything else.