My thought here would be that it benefits the knight more to have a split between rate of fire and damage. That is to say that one attack speed increase and one damage increase would increase performance, by more than 2 ASI or 2 Damage.
Which means that if you're a sword user, then bringing along the claw kat hat alongside vog or skolver would not benefit you as much as would bringing one piece of vog and one of skolver.
But what would benefit you would be bringing the claw kat hat alongside something like volcanic demo; this would let you use bombs with much more proficiency at the cost of some of your sword damage/attack speed.
Another example would be one where the user wants to use argent peacemaker alongside a sword; using a piece of vog and barbarous thorn shield alongside the kat eye hat would yield the user improved handgun performance, as well as balanced, meaning optimal sword damage.
Agree? Y/N
Either way, I'm testing this out at some point, probably soon. Vog+bts+eye-hat/bomb hat, or even sword hat, should get me nice, yet subtle, results.
Although there are some deviant cases (such as the shard bombs), we know that each level of damage bonus is about 5% (based on the Lancer Knightz data --- the wiki page "Abilities" says it's about 7%) and each level of ASI is about 3.5%. I don't remember the effect of CTR, so I'll confine my remarks to regular attacks.
If you simply want to increase DPS, then max out damage bonus first, and then get ASI if you have more room for bonuses.
If you want to go for kills per second, then ASI will always help you by 3.5%, whereas damage bonus will sometimes not help you at all (you still kill the monster in three strokes) and will sometimes help you dramatically (suddenly you kill the monster in two strokes). The obsessive number-cruncher would know how much health the monsters have on each level, based on the number of knights in the party, and would fine-tune his damage bonus accordingly.
You know all of this, I'm sure. So maybe I'm misunderstanding your question/comment.