I've been reading through a lot, and designing an Inquisitor for my players, and just noticed two things. Firstly there's a reason to use two weapon fighting; if you hit your opponent with a flurry of lighter strokes like a knife or fist first, you can get him up to a high Wound rating so your second, heavier pistol or sword stroke can finish him off. I actually like this idea, as that's a pretty cool fighting style and gives the Desperado a sweet specialization. This is especially the case as, as the example of a character taking multiple hits from one flurry of blows indicates in the book, you don't start stacking on the +5s for multiple wounds until the next ATTACK roll. Thus, you slam a guy with a series of light hits to rend his armor and get him on the backfoot, then stick him through the head or throat with a heavier finisher. Neat, and a cool reason to use a heavy and light melee weapon in tandem.
The problem is, the Inquisitor is designed as a higher rank (Rank 6) character, as an exercise in seeing what happens as characters get up there, and his chainblade/chainsword combo is attacking significantly faster than a heavy machine gun or other automatic weapon, at like RoF 6 with the blade and 4 with the sword. He attacks faster than the cyclic rate on a heavy machine gun. I want you to think about that for a moment.
I would suggest that perhaps Rate of Attack should be uncoupled from Agility Bonus. In a game where players are going to get much higher stats over time than they did in the original Dark Heresy, the numbers are just going to get absurd over time, compared to the rates of fire on the automatic weapons listed earlier. I'm also not sure how I feel about the fractional RoF weapons, and I suspect weapons with a very limited fire rate could be better represented by adding Single Shot to an RoF 1 weapon, though I cannot confirm this without having done actual playtesting yet, as we're still designing characters and preparing.