Often I found myself just willing to edit one metrics (e.g. to change it to one of the graphite availables wild cards, say {foo,bar} ) but I have to edit the entire "line" by clicking on the pencil for the query. It'd be great to be able to just edit a metric by clicking on it maybe by adding an identifiable icon (pencil?) when clicking on the metric instead of just the list of available metrics as pulled from graphite?
Also when doing such editing it helps to know what metrics are available, so ideally I would click on a metric then edit by clicking the metric edit icon then type "{" and a pop up menu would show the list of possible values, from there I would either type (with autocomplete available) or click on a metric value then type a "," and another pop up of available values shows, etc.

I can understand this not being a priority at all but I thought I'd share some feedback about it.