Also I think you used purple wool for color but now I think its holding
your building creativity back and you should replace it with an upgrade to
Purple Stained Clay.

Keep the Nether brick and the sand stone slab floor. Those look Good
together, but break up the floor with some exposed Nether rack and go ahead
and make your dome (Nether brick???) ceiling but break up the dome with
more exposed Nether rack. :)

[Maybe the dome ceiling was once Nether brick but the Nether rack is alive
and it push thur and Glow stone is hanging in an organic way inside the
nether hub helping with the lighting.]

Your Nether tunnel look good as it is but you could just finish the theme
of making it look worn down by having exposed Nether rack and then you
could add Crack stone bricks as well just to break up the pattern.

Purple stained glass might enhance the over all look of the nether hub
tunnel as well.

and it might be strange I dont know but perhaps you could try adding pack
ice into your sand stone. I think you were right about the unbroken pattern
with the sandstone floor and pack Ice seem to have that same unbroken
texture.

Pack Ice, Snow, Sandstone, Purple Stand clay, Nether brick, Netherrack,
Stone brick, Crack stone brick, Iron bars, and Purple Glass, as well as
Redstone lamps and maybe Sea-lantern blocks? If used wisely could for the
foundation of all of your nether builds not just the Nether hub.

I think your Mindcrack builds and Ethocorp style look good and you should
use it more often instead of worrying that it will get repetitive. Its
Etho’s style. :)