I also agree with this, one hundred percent.
It is only too true that we all require slightly different settings to feel comfortable. But:
Extensions, userscripts, and various other "Band-aids" are all very well, but making lots of us use multiple third-party resources to revert the various poor design choices made by Stack Exchange is...not great.
It's obvious enough that:
The proper solution requires ability for each user to customize line height (and possibly other settings) in the site itself, without needing to use userscripts and other external tools.
It would be great if we could add this as an option in user preferences. I am utilizing @Prid's excellent Chrome extension, but being able to customize the settings (or at least some), without various userscripts and extensions cluttering my browser, would be wonderful. This would make for an easy-to-use, more comfortable site, and a better user experience. Not for some, but for all.
EDIT:
I'm so hot on this idea, I made a few screenshots of what it could look like:
And, for the line-height:
This would really be great.