Dungeons need some spice!

[Shurrikhan]

except the way i see it is that people will see that a mythic + system is there and they'll step into it when they're clearly not supposed to be there (just like every ex/savage piece of content)...

Isn't part of the beauty of a Mythic + system largely that it can be easily configured not to permit access to a given difficulty level until you have finished the level immediately before it? Beyond that, the situation is identical to that of Savage.

For the very first Savage dungeon, your only safeties are the completion of Normal mode and a higher ilvl requirement. For each thereafter, it's completion of the difficult content immediately before it. In Savage, that means E5, 6, and 7 for access to 8, for instance; in "Mythic+" that means Savage, +1, +2, and +3 for access to +4.

We're free to add further restrictions, such as SSS output, ilvl, or prior level completions, beyond WoW's incredibly loose requirements (largely for the option to carry friends, especially since their levels scale up separately for each week, always starting from 0 and thus forcing the strongest players to briefly mix with the weaker participants).