I would say there's still clearly a problem when the Black Mage and Red Mage population combined barely edges out the Summoner population at high end play today. And I was one of the people that constantly argued how it was stupid that Summoner and Red Mage were that far behind Black Mage during the first tier of Eden, and that the huge 'raise tax' was an oxymoron because if there was a point where a caster actually needed to use raise, the run is probably a wipe anyway. (Though the bigger problem then was the big disparity between the top 5 DPS and the bottom 5 during that era as well, while this obvious gap no longer exists today except towards the very bottom.)
That said, I would think Summoner does too much for all they're capable of, except I noticed the gap between Summoner and Black Mage can actually be explained by the existence of Devotion. In that case, taking away Raise would probably be enough, so then it becomes an exclusive trait of Red Mage.