Last Guy in the Airlock
Right, but maybe in testing the +2 bonus wasn't competing well enough for spellcasters against a feat.
Pure speculation, of course. But consider - for a martial class, a bonus to the primary combat stat will boost attack *and* damage. For a spellcaster, it only boosts attack. Having a little bit more to give up when you take a feat would tweak the balance a bit.
That's interesting, if true: if so, our play tests (across several groups, though admittedly with some overlap in players) consistently could sell feats to non-casters early, but never casters.