Yeah. I agree with the OP that I would really like to see the old layer screen back, or even better an improved version* which is a hybrid of the two.
As it stands the last ~5 games I've played the map has been completely devoid of iron and/or flux so a decent steel industry has been out of the question. I really just want to be able to tell the region generator to force an area to have: river, deep soil, sedimentary layer with lots of iron, flux, sand and some interesting caverns. The whole world map is great in theory, but when you need to generate 2 or 3 worlds just to find a suitable site for your next fortress design it is more a hindrance than a benefit. It is even more annoying when you realise that once you embark the world outside your fortress has no real effect on gameplay and can be reduced to maybe 10 values: weather patterns, civ access, civ proximity (goblin attack frequency and caravan arrival times, etc), ... actually I think that's it. I know that it will be improved with the trade an military arcs, but for now it just seems a bit overkill and ends up just getting in the way of fun. I don't think it should be removed by any means, but I disagree with any changes which reduce the available information about the resources available at a site for the sake of realism.
* Here's an idea I thought of for the layers screen. I like that it lists only interesting stuff such as flux and 'metals', but I would prefer a bit more detail. As such, it should display something like this:
=========
4 Soil (SAND, AQUIFER)
5 Sedimentary (FLUX, METAL)
17 Igneous Intrusive (METAL)
8 Metamorphic (FLUX)
12 Igneous Intrusive
=========
In this case the various tags (SAND, FLUX, METALS, etc) would be specified by raw tags of the form [LAYER_DISPLAY:<NAME>] where name is what would be SAND, FLUX, METAL, etc. The numbers next to the layers indicate depth, though this could be varied to be anything from tags like 'SHALLOW ', '', 'DEEP ' etc to exact z-level counts.
I should probably actually post this in the suggestions forum at some point.