After reading this post, I'm really bothered by what seems like a trend. Complicated components. As once you were able to tweak with disc brake rotors carrying only a T-25 torx, now you might need a cassette lockring tool and wrench. Here's another example. We just finished reviewing three high-end cranksets. In that review, you'll read that the FSA crankset uses torx bolts for the chainrings. Overall, I think this is a great idea. However, when I got out my T-25 (that I carry for my disc brake rotors), I found it wasn't the right size. As it states in the review, FSA uses a T-30. My old mult-tool doesn't have a T-25, and I'm certain that most, if not all, new multi-tools (that have a T-25), don't have a T-30. So, there's another wrench to carry.
Now, I know that most trail-side repairs can be avoided by checking your bike BEFORE a ride--and I highly recommend it--but, that won't always prevent trail-side problems. It might be nice, when you're 15 miles from the trailhead, to be able to fix your bike, rather than drag it out.