I would like to consider the ability to customise the labels for the GaugeRange items that may not be part of a numerical index. For example, you may have a 3 range gauge that is low (green) / medium (orange) / high (red). Currently there is no way of customising these values. I believe this would be similar to what is currently done in the Slider control ( http://demos.telerik.com/aspnet-ajax/slider/examples/slideritems/defaultvb.aspx)
Actually using the label templates doesn't solve the problem. The labels are dumped as per each min/max values of ranges, while the goal is to have them shown in beetween the range, just like the slider control. I also attached an image that perfectly shows the scenario. It should a new great feature for gauge.
This could be done via label templates so you may want to try the approach there and cast your vote for that feature as well: https://feedback.telerik.com/Project/108/Feedback/Details/138880-add-templates-for-labels-in-radgauge