Then came the comments. Nothing really wrong with any of them, but the whole “layout is not the only thing that should concern you; performance/context/content/blah is also (maybe even more important)” thing is getting very tired. Why? Because nobody is saying those things aren’t important.
Here’s a fact: If the homepage of site [x] is 100kB, then it’s 100kB. If I make that page look decent on several devices via adaptive layout—unless I go overboard—it is still going to be 100kB. Okay, maybe 101kB. It’s either zoom hell or not. So people can complain about that, but unless they’re willing to add to the client’s budget, the extra layout flexibility is (often, not always) a relatively quick readability and usability win. Device-agnosticism should be baked into the design approach anyway. There’s absolutely no harm in it.
So no, do not ignore content strategy and performance. And if you do content strategy, then you’d do well to be thinking about design. Device-agnostic design applies here as well.
Don’t feel bad about doing adaptive layout just because these other things are also important. It’s okay. Really.