Getting max knockdown is just way too easy and the percentages are really high. I get a knockdown on someone and I can get a held+speed bonus hit while they're helpless on the ground (and possibly a kick+another hit). That's actually worth more than a 2 extra hits since you can line up your swings at your discretion. Knockdown when fighting happens so suddenly that getting the cumbersome-to-control roll off is highly improbable.
In a 1vX, knocking someone down gets him in the way of his teammates and opens even more openings to get hits in.
As I stated earlier in this topic, increasing the raw damage to 80 makes it so that only really good held hits or highly damaging weapons can reach the maximum %. Some weapons (most notably 1hs) need to have a lower weight so their maximum % chance to knockdown is decreased, especially since they're the easiest to get hits with.
All of this allowed me to achieve ridiculous performances in strat battles over the last few weeks with only 6PS and +3 warhammer (and +3 iberian on one map).