Unfortunately my test campaign does not include any melee-oriented players so I cannot speak to the melee RoA situation besides the occasional dabbling imposed by charging npcs, but I do have a psyker and my group has used a wide variety of weapons on their rise to rank 5.
We came to this conclusion:
Multiple action point costs to fire a weapon or attack are crippling and destroy much of the flexibility and choice that APs added to combat.
My PCs hated using weapons that had a fire rate of 1/2 and quickly discarded them in favor of higher RoF weapons. This was not because they all had high BS. Even the techpriest with relatively unimpressive BS preferred higher RoF weapons simply so he could move in and out of cover, avoid melee, reserve AP for evade reactions, aim, make called shots, or otherwise do interesting things.
We have house-ruled nothing so far except this. All attacks that called for multiple AP for a single trigger pull or swing got altered to 1 AP. All those that were formerly 1/2 were given a totally made up "double shot" quality for the purpose of limiting them to a max RoF of 2 per round (using two AP, one for each shot). This is not a shot every other AP, but it was a relatively clean change otherwise. Anything with 1/3 or 1/4 for a RoF was then given the single-shot quality. This means more aiming or movement or whatnot can happen with slower firing weapons without dramatically changing the overall RoF-balance situation.
APs are, as actions always are in rpgs, the most valuable currency a player has and taking them away in big swathes just to fire slow firing weapons seemed unnecessarily punishing.
This same logic extended to the group's psyker. The psychic powers, even after spending 1000s of xp on PL and WP, were not compelling alternatives to the psyker just shooting whatever guns were lying around. In fact, the psyker still makes extensive use of autopistols, a sniper rifle, and a looted plasma pistol because even at PL 5 then range, RoF, pen, and damage of most weapons beats out nearly all psychic attacks. This is even true with easily accessible weapons that likely do not even require a 300xp proficiency and need only an easy acquisition roll or even come default with a character.
Making Psychic attacks take a single AP might make them outstrip some pistols, but they certainly do not compare with melee scaling, dual wielding, plasma, or even the now somewhat tame bolt weapons. Of course the stealthiness of carrying around such weapons compared to being a psyker is always a feature, but using psychic powers is not without risk and is arguably a lot higher profile in terms of subtlety, and at least as of now, many more talents allow the boosting of BS attacks than psychic ones.
Personally I would love to see a psyker dual wield a weapon and warp based attacks. I think it would interesting and evoke the setting. The tendency to shoe horn psykers into a scholarly role is silly in my opinion, and certainly not appropriate for many of the psychically powerful inquisitors and their agents in the fluff. Not everyone has an Abnett-vision for their campaign, but I like my Eisenhorn and Ravenor-style group compositions and would love to see the gun-toting, combat oriented, and street savvy psyker be easier to implement.
Edited by Togath