Bukkit

What is the enhancement in mind? How should it look and feel?
Many dynmap icon plugins allows an option to have the icon be toggled on or off at default when the dynmap page is loaded.
Ex: Worldguard/Towny regions, or dynmap-mobs. They allow having them displayed on page load, but be selected to show when the user checks them.
xWarp allows selecting which warps to show on dynmap, but no choice if they show up by default on page load, but users can disable them if they want.
I would like to be able to either:
a: Have all warps not show on page load
b: select which warp types to show on default, but let users select which kinds to show themselves.

I currently have all global warps set to show, but as you may guess, setting public warps to show would cover the map. Hard to tell which is global and which is public if both are enabled currently. I would like to have all global show on page load, but public toggled off and allow the user to choose if they want to see all the public warps.

On your first point, you are able to hide sets of icons using the dynmap commands.

Using the command:
/dmarker listsets
This will show you all the sets and one of them should be "xwarp.warp.set0 label:"Warps", hide:false, prio:0, minzoom:0, showlabels=null"

Then do the command:
/dmarker updateset Warps hide:true
This will make the warp set hidden on page load, but can be viewed when toggled on.

As for your second point, I agree. Having 2 different sets of icons would be nice.
So say the config looked like this, with the addition of hiding as an easy option, rather than using dynmap commands,

marker-global:
  enabled: true
  png: marker-g.png
  hide: false
marker-public:
  enabled: true
  png: marker-p.png
  hide: true