That is very nice that you are adding meseportals back in the game but I really hope you change the texture and shape of the portal, because I mean circles and block games don’t mix.
And about the progression? I think that is a very nice Idea, similar to Minecraft’s progression system which is Overwold>Nether>End. Right now, if you make it where you dig to hell, there would about 1 person trying to do it, because the Nether is pretty boring and the only thing useful there at the moment is glowstone, air portal blocks and maybe nether tools? But there is still no armor for that, soooo yeah, the nether needs an upgrade. But from a player’s perspective I see it the progression going similar to this: You start on the Overworld, then dig down to get minerals and other resources, You may find obsidian which can help you get to the nether and help you find better gear such as nether tools (Which hopefully becomes an actual ore instead of smushing netherack together), While at the nether you may find some old portal blocks that can be used to take you to the Cloudlands, a section of the world that harnessed magic to be safe from corruption. While there you have a chance to find giant trees, and taking their hearts, which have magical qualities, may help you progress. Then we turn back to the mines, where if you dig deep enough you might find a type of rock called Slade that even diamond tools can’t break (Maybe this is what nether tools can be used for) while there you might find some meseportal fragments which, with combining with a heart of a giant tree, you make a meseportal that takes you past the magical barrier set by the evil corrupted lizards and on to the moon of the Mesecraft planet. Here you can find ores that might give you special abilities like speed and jump boost, or maybe even gravity boots. Here you can also run into Alien outposts which you can maybe get the way to get to the final progression: Mars (Or as I like to call it The Homeworld. This barren desert realm (Which hopefully you can add air here as we established awhile back this wasn’t mars) is the homeworld of the lizards and if you scout out the land you can find a couple of special item that maybe will spawn the boss?
Anyways that’s how I would do it in my head. And places like The Primordial and the asteroids could be bonus places.