Normal dungeons > Heroic dungeons > Mythic dungeons > Mythic+
LFR raid > Normal raid > Heroic raid > Mythic raid
You could literally not step foot into a raid and play Mythic+ as your main way of gearing, never seeing any content in raid beyond LFR just to experience the story, and you can hit item level 475.
Want to experience harder content? time commitment. Grinding dailies. RNG gear drops. find a guild. find 20 other people for mythic. Do visions. Do world bosses. Farm for gold to afford to raid. ect.
There is a reason that WOTLK had the biggest player base ever in Warcraft history, the game was easy. There was meaningful progression, when you were done gearing in dungeons for that patches current gear, you would look to find a 10 man or 25 man normal raiding guild. The content wasn't that hard, people had fun being able to clear the content, or learn the content together with their guild. I remember Naxx being easily puggable, Ulduar also wasn't half bad.
The point I am trying to make is that there's simply to many ways to get gear. Raids used to have this feeling of curiosity and people wanted to explore them. Instead of making it widely available via LFR, you had no other choice but to either commit to a guild to see the content, or you didn't get any better gear. It was that simple.
I'd rather see a system like this again then the current. I came back after a 5 year hiatus, found a guild to do Mythic+ and start raiding, and cleared LFR Nyalotha to see the content because I'm so many months behind on my cape. SO many trolls in LFR now, just ridiculous that this game mode is even still in development.
What are your thoughts on how raiding/gearing is laid out?