I've done one hard reset in about 8 builds of W10m, and that was only because I did an elective firmware update.
My (and all three of the W10m phones in our family that I keep track of) phone spins right along, and has gotten progressively better battery life, functionality as per release spec, etc.
While I don't debate the validity of a fresh install (I used to do OS development, and we were always doing this, mostly for testing, but also for dog-fooding), I don't really think it's necessary every build, or really even on a release, unless you're having indications.
It can definitely "reset" everything, and often increases performance a small amount, but it comes at a cost, and sometimes OS tweaks bring the same performance, from a later build(s).
Right now, the cost is high, as Restore isn't working really well, so a lot of settings and the like must be manually fixed after a reset.
If the cost were low, I'd consider a reset, after RS1, maybe.
I think telling everyone they should just "hard reset to fix it" is a bit harsh though. I get that it can often fix the issue, but so can digging in a little and doing some diagnostics; I've probably fixed 95% of my OS problems this way. Is it easier to tell them to just reset, yep, but the "right" way to do it, well, that's probably philosophical... ;-]