Recently I looked up the mechanics of Dispells and Counterspell Combat Mode, tried the latter in game and had a short, but enjoyable RP experience. So as another spell caster's combat mode which is rarely used (defensive casting), I wanted to add it to my Quickslot bar, but was unable to do it. At first I wanted to report it as a bug, but made a random campaign game and saw the same thing, not really categorizing it as a "bug".
I wouldn't know the exact proportions of classes played on the server, but I think there are a bit more casters than non-casters, if not a same amount of both. I couldn't also know the reasons why Counterspell isn't often used, but how players cannot have instant access to it may be a part in this. I don't think it's necessary to give a list of situations where this mode could be useful, despite early and late PvM, PvP or even just pissing people off because counterspelling doesn't break invisibility.
As for a suggestion for the Team... the first thing that comes to my mind, despite how many counterspells there are stocked in a list (as I think it is), is to, if possible, add the targeting cursor to the Mode... Even if it sounds somewhat "too-easy" {since Counterspell can only be activated using the radial menu on an enemy ~4 clicks, huh}. Just that could solve the "problem", from my perspective.
Of course, if nothing can be done, everyone can live without.
Hero~