The 'fix' of the 6-8 encounters in an adventuring day misses the mark. Yes, if your view of an adventure is a dungeon crawl, that 'works' so far as not letting players recharge, but that paradigm fails on a basic storytelling principle:
The basic structure of most action-adventure stories don't fit the 6-8 encounters. Seriously, think of all of the comic books and fantasy stories. There are very few in which a hero is expected to overcome that many obstacles on one tank of gas. Just going with Batman, off of the top of my head there's Knightfall and that's about it. And even in Knightfall Batman got to replenish his utility belt. What's more, a lot of stories also allow their protagonists to recharge in a day, maybe a couple if they're seriously gassed. Not a whole friggin' week unless they're completely totaled. Because while a lot of stories don't start new adventure arcs on the very same day, a lot of them only give the hero one or two days.
Rather than doing narrative violence by forcing the game and story to fit around this arbitrary paradigm, why not instead just, you know, reduce the encounters between rests?