got legacy tree icons showing up now, added a couple of filters for this to work.

src/Umbraco.Web.UI.Client/common/filters/treeiconclass.filter.js

@@ -0,0 +1,21 @@
+'use strict';
+
+define(['angular'], function (angular) {
+
+    /**
+    * @ngdoc filter 
+    * @name umbraco.filters:umbTreeIconClass
+    * @restrict E
+    * @description This will properly render the tree icon class based on the tree icon set on the server
+    **/
+    function treeIconClassFilter() {
+        return function (treeNode, standardClasses) {
+            if (treeNode.iconIsClass) {
+                return standardClasses + " " + treeNode.icon;
+            }
+            return standardClasses;
+        };
+    };
+    angular.module('umbraco.filters').filter("umbTreeIconClass", treeIconClassFilter);
+
+});

src/Umbraco.Web.UI.Client/common/filters/treeiconimage.filter.js

@@ -0,0 +1,21 @@
+'use strict';
+
+define(['angular'], function (angular) {
+
+    /**
+    * @ngdoc filter 
+    * @name umbraco.filters:umbTreeIconImage
+    * @restrict E
+    * @description This will properly render the tree icon image based on the tree icon set on the server
+    **/
+    function treeIconImageFilter() {
+        return function (treeNode) {
+            if (treeNode.iconIsClass) {
+                return "";
+            }
+            return "<img src='" + treeNode.iconFilePath + "'></img>";
+        };
+    };
+    angular.module('umbraco.filters').filter("umbTreeIconImage", treeIconImageFilter);
+
+});