Bridge sort by number of keywords...

Okay I dont't think you will get what you want, here is a very poor compromise.

To Install see Prepression: Downloading and Installing Adobe Scripts

This script creates  a tabbed palette, in the bottom left hand corner of Bridge

Once you have selected your folder click the process button.

It will create a list of all files with the number of keywords associated with it.

If you click on a file name in that window it will reveal that file and select it.

Hope it is of some use?

Also it will tell you how many keywords in total there are.

N.B. You need to click process if you change folder to update the details.

The font is very small but due to Adobe not fixing thier bugs there is nothing I can do about it, last good version was Bridge CS5 and it has got worse with every new version.

#target bridge;
onDocLoadEvent = function( event ){
if(event.object instanceof Document){
    if( event.type == "loaded" ){
          $.sleep(1000);
                keyCount();
            }
        }
        return { handled: false };
}
app.eventHandlers.push( { handler: onDocLoadEvent} );
function keyCount(){
try{  
sPalette = new TabbedPalette( app.document, "KeyTest", "test", "script","left","bottom");
pnl1 = sPalette.content.add('panel');
pnl1.alignChildren="left";
pnl1.addBtn = pnl1.add('button', undefined, 'Process');
pnl1.txtF = pnl1.add('edittext', undefined, "                                               ");
pnl1.addBtn.preferredSize=[50,25];
pnl1.txtField = pnl1.add('listbox');
pnl1.txtField.preferredSize=[200,200];
//should work but doesn't blame Adobe!
pnl1.txtField.graphics.font = "dialog:24";
pnl1.addBtn.onClick = function(){
pnl1.txtField.text ="";
var thumbs = app.document.visibleThumbnails;
var List =[];
var tCount =0;
for(var a in thumbs){
if(!thumbs instanceof File) continue;
var md = thumbs.synchronousMetadata;
try{
md.namespace = "http://ns.adobe.com/photoshop/1.0/"; 
var count = md.Keywords.length;
tCount += count;
List.push([[decodeURI(thumbs.spec.name)],[count]]);
}catch(e){}
}
List = List.sort(function(a,b){return a[1]-b[1];});
List.reverse();
pnl1.txtF.text = "Total Keyword Count = " + tCount.toString();
pnl1.txtField.removeAll();
for(var z in List) {pnl1.txtField.add("item",List.toString());}
pnl1.txtField.selection=0;
pnl1.txtField.onChange = function(){
app.document.deselectAll();
app.document.select(new Thumbnail(app.document.presentationPath + "\\" + List[this.selection.index][0]));
app.document.reveal(new Thumbnail(app.document.presentationPath + "\\" + List[this.selection.index][0]));
    }
}        
sPalette.content.layout.layout(true);
}catch(e){$.writeln(e + "\n" + e.line);}
};