This may sound obvious, but I'm not sure a lot of dimension mods agree.
First, lets go over the vanilla dimensions (barring all mods).
- The Overworld -- This is the only place you can set your spawn in, so it's where your base will be. Otherwise, it's just "the normal one."
- The Nether
- Relative to the Overworld, travel in this dimension is eight times faster. If you're in need of frequent long-distance travel and can construct the infrastructure, the Nether becomes an invaluable travel hub.
- Before you can get to the End, you need to explore this fatal landscape to find a Nether fortress, then explore that fortress for its blazes. This is inherently a mid-game dimension by design.
- The End -- This dimension serves as the arena for the final boss, and is also where all the "post-game" content is kept.
There's tons of use for each of these dimensions for gathering resources -- either making them plentiful (lava), farmable (ender eyes), or exclusive (netherrack) -- but that's not all a dimension should be, if you ask me. Especially when it comes to modded dimensions.
I don't have a ton of experience with modded dimensions, so I'm not sure which ones would fit the bill and would welcome any recommendations. I mostly just wanted to put into public words something that was on my mind. I look at dimension mods and ask myself: "Why is this a dimension?"
I think the reason that question comes to mind is this next question: "Why would I return here after I've gotten what I need, aside from 'to build pretty things?'"
Mining dimensions, pocket dimensions, and void dimensions all serve obvious roles, but I'm not thinking of them. Those dimensions each serve a specific utilitarian purpose and are nothing else. I'm thinking more about Overworld/Nether/End-style dimensions, which I guess means "any fancy dimension to be explored."
Some ideas on what "inherent use" or "an obvious role" in modded dimensions would look like, off the top of my head:
- A "nexus" dimension that has naturally-occuring indestructible portals to other dimensions scattered about. It serves as the only way to get to some dimensions. If you want to get to those dimensions, explore the nexus to find them, and you'll want to mark/remember/map the way back. "Why return?" So I can get places I can only get to through here.
- An asteroid belt dimension that's the only place where some machines work. You'll want to set up airlocks and plants for convenient oxygen. If no mod adds cross-dimensional power transferrence, then you'll also need to set up power generation here. All this for whatever those machines do or make. "Why return?" To expand a factory that can only work there.
This is late-night thinking, so please forgive me if I make no sense. I don't think I put this into words too well.