This is obviously a very good change for the people who matter, which is those that want M+ to be a challenging, competitive, and self-contained experience, as raiding and PvP are.
The fact that the rest of the players can benefit from it in any shape or form is accidental, and any self-entitlement in that regard needs only be dismissed. Just as people who aren't into PvP or are not particularly good at it sometimes dip into it to get some PvP gear to use in other content (heavily mitigated by the reasonably recent changes that make PvP gear only really competitive in PvP environments), M+ should not be for people who want their weekly grab bag of free top-tier loot to use in other content, and this is a step in the right direction - and hopefully, there will be more of it coming soon in that same direction.
I see people tagging it as elitist as if it was a bad thing, but it's in everything in life. Every job, every sport, every game offers more rewards to those who are better at it. And I'm very glad M+ will reward those who are better at it. Get over it.