I think the problem with polearm swing speed is tricky. First, polearms seem to have the animation in which the weapon reaches maximum extension the quickest. In other words, turning into your swings is much more efficient with a long polearm, as other categories perhaps won't glance when not yet inside their sweetspot, but will probably miss due to poor reach. Second, polearm animations seem to be skipping frames and are generally jerky compared to smooth 2h or 1h swings, hence why I often find myself lacking time to block a polearm after the swing is released, even though there's no real problem doing that against fast 1h or 2h.