Currently clicking on a disabled breakpoint in the margin removes that breakpoint. It seems more intuitive to click the breakpoint to enable it. This is especially the case since a programmer is more likely to temporarily disable a conditional breakpoint for performance reasons, and accidentally removing the breakpoint results in a great deal of additional work to make sure the same condition gets entered.
This can be taken as an enhancement to do something in this regard.
Currently the click is used to toggle the breakpoint (add and remove). Thus it's symmetrical. Allowing to enable the disabled breakpoint by click as well could bring confusion into what the click does IMHO.
From the debugger's perspective, a disabled breakpoint and a missing breakpoint are equivalent. This makes the current behavior not symmetric - clicking on one binds the breakpoint, but clicking on the other leaves the breakpoint unbound and instead deletes (without any undo available) any work you performed configuring the breakpoint.
How about supporting ALT-Click on the icon? This will toggle the breakpoint status from enabled to disabled and viceversa. (Seen in IDEA)