Yikes ; all one layer could be a pain to recover from. I bet you're already loving working on separate layers, eh?

I dont know if this is much better - there is maybe some more evenness between differently sourced symbols, but it's at the expense of contrast.

Your southern mountains seem to have some east-west reversal; see how the two biggest peaks are lit from the right, while everything else is lit from the left?

Looking at the mountains I see just a couple in the north with sharp outlines... Have you been resizing these symbols? That'll leave them murkier than the original under most conditions. if you HAVE to resize them, maybe you can draw in thin, dark edges to "resharpen" them. Do you have access to a tablet and pen, or are you drawing lines with a mouse? A digtizer pen would make such enhancement easier.

The desert wastes in the center are going to be tricky to get across to a viewer. One thing they need is for the river layer to go above the wasteland symbol texture. Another bit that might need rethinking - if it is arid, where did that lake come from, and how is it overflowing to start a river?

I guess it does look older than your first parchment rendition, if that's what you want.