I don't want to see it shut down, but I'm biased. I've known one of the people associated ( @
Ulsoga ) since before WoW was even a thing that most people knew was going to be released. So on one hand I like seeing raider.io being successful.
On the other I really don't like what it's done to the M+ community, but that's not Raider.IO's fault, that's players using things in a way that's inappropriate. It's obscene overkill to use raider.io for anything below a certain threshold, but people are going to do it anyway. It's like GearScore, there was nothing really inherently wrong with GearScore, it's how people used it.
Honestly if you don't like raider.io, don't use it. Make your own groups and don't set any requirements based on raider.io. That's what I do.
They're not giving out "absurd amounts of ilvl" - Your ilvl is determined by the content you do. Someone that only does say normal or heroic is going to have much lower ilevel than someone that does Mythic, unless they're also doing a shitload of M+, in which case they deserve the high ilevel because that's how the system is designed to work. Plebs aren't running around in super high level gear from low content, that myth really needs to die.