They changed it in HW after Gordias because everything but tower shields were noob traps due to Sheltron. Ironically, now that shield oath generates Oath through blocking, the "rate vs strength" choice would have actually had some merit for both sides.

Oh they also removed varying sword delays. Lower used to be better because of Sword Oath. Then they normalized Sword Oath, and I think in the same patch they stopped giving out non-standard sword delays. Fastest would have been best in SB again because of gauge generation. Also there was a possibility that Skillspeed might have been kind of interesting for paladin/ninja gauge generation, but speed ended up just increasing auto attack damage and not actually making it faster.