My Gale mostly uses lv3 counterspell unless I'm seeing a really deadly spell cast, and for the most part it often succeeds. You're probably having bad luck. Granted, most of my usage has been in Act 3 and by then your characters are decked out in a bunch of +1/2 DC enhancement gear plus rocking 20-22 of their main stat.
DC enhancement gear should be irrelevant in that calculation; it is a raw stat check. My sorceror's charisma is 22. Anything not exactly the same level or above always fails, 14 times now. Given how no roll is ever shown, and the name of the spell changes into Failed Counterspell in the log, I can only assume the functionality is outright not in the game.
If you want, check the level of spells you are counterspelling, and with what.
