Someone said
Which is completly insane. I got 870, which means I should do +12 to get solid upgrades BUT I can't even get invited to +5 with my ilvl. This is why Mythic+ sucks, as people are so insanely ilvl hornyLvl--Base-Cache
10 = 865-- (880)
11 = 870-- (880)
12 = 875-- (885)
13 = 880-- (890)
14 = 885-- (895)
Why isolate M+? The fixation with iLvL in the pug scene has always existed, essentially because people want their pickup groups to be as painless as possible. I see this echoed a lot, and while I certainly agree that iLvL doesn't equate to skill, I fully understand why people do it. Pugs are built around you not knowing who you're inviting, it's only natural that the only metric we see (iLvL) is the one that determines who gets into groups.
I'm curious as to why you wouldn't get invited to groups. For most people like me who do M+ a lot I generally don't look at iLvL unless I'm doing something above 10, as the chances to +3 with really low iLvL people on certain affix weeks becomes increasingly difficult. While generally I do M+ for the AP (and thus beyond 10 really isn't that efficient generally), I will oftentimes take somebody with a good key on a higher keystone than normal if I think we can +2/+3. People generally don't do M+ for the base rewards, but it certainly is easier to get the good rewards if the base gear is at a higher iLvL (naturally).
Keep in mind what I posted about *speculated* ranges is only that, speculation. Furthermore I don't see what's necessarily wrong with those brackets. Those levels are getting easier and easier, and you're seeing more carry groups do 10-12 range now, as opposed to a couple months ago when the highest people would take 7-9 at the upper echelons. Everything is moving upwards, so it's only natural M+ does as well.