I'm currently playing my first DH adventure and chose the psyker class, as i really feel this is of the WH universe we should experience in our group. Now as I just reached rank 4 and thus psy rating 3, our GM decided to go with the "Effective psy rating" house rules he found online.
This means every time a power uses WB, this should be substituted with "number of dice rolled while activating the power". As I've played various systems over the years I can see that certain powers can get out of hand.
Psy blade being one. As I have Will 65, soon maxing it to 70 (whenever i can scrap together the last 750XP) it would be an awfully powerful weapon, having 70% chance to hit, d10+14 dmg and pen 14. Using the EPR and rolling my maximum amount of dice (3) instead it would now be 70% hit, d10+6 and 6 pen. Still a ok weapon, especially as my psyker sucks in melee, this would give him an option to at least give back some damage.at Max level using 6 dice it would be again +12 and 12 pen. However at this point I assume that once we're at that level, the others would have fighting abilities matching this some way or another.
The above example I feel is pretty balanced with what the rest of the group can come up with in firepower. Given that a psyker must take the risk of the oh-so-fun warp phenomena and perils. Which I've already been hit a few times with. Not too bad yet, some insanity for the group and a few points of corruption for me. However I feel that almost all the other damage related powers are nerfed to uselessness. As I meant to take psy blade for my first psychic power, I decided instead to go with seal wounds as the EPR affects it less (and we always need the healing anyways) so I took biomancy. I did however mean to take Telekinesis to get various powers there. Though now they mostly strikes me as quite weak, at least when only rolling 3 dice.
For eksample the force bolt will be maximum 70% hit chance, d10+3 (possibly +1-3 more on overbleed) for a ~27% chance of a phenomena. While I agree with our GM that phenomena is mostly "fluff" without too bad effects, it's still a ~7% chance of a Perils effect which seems to be can be quite damaging.
The same goes for the biomancy "bio lightning" that appears to be the only pure damage power. If i buy this with the XP we got last session, I can do d10+3 dmg. Granted the lightning appears to automatically hit, and one can potentially get may be 1 or 2 more bolts (but i wouldn't count on this too much). I'm guessing our opponents are in the range of 3-5 toughness and 3-5 armor so far.
It seems to me, especially given the force bolt, that simply firing my simple auto gun with regular ammo is just as good (base 44 BS) on full auto. No 7% chance to permanently injure/kill my own character and/or the rest of the group. Even force barrage doesn't seem all good, firing about 3 (possibly 4) force bolts compared to simply having a long las with red dot sight (and possibly topped off with uncanny aim, that can be activated with a single die). having the potential to do 3d10+4 (and i believe getting a few hotshots packs shouldn't be impossible either).
Some info that might be useful to know:
* I generally use invocation, if possibly, before using the major power I have (at the moment seal wounds) and will probably always do so.
* I don't see it's likely that our GM will ever let me get unnatural willpower
* Telepathy and Divination are barred for me, I'm not allowed to chose powers from these diciplines.
Now while I can appreciate effects such as "always hit" (bio lightning), having "infinite ammo" and simply having damage power ready in case one gets stripped for equipment, I feel as long as I can get my hands on almost ANY reasonably common type of weapon (autogun, long las..etc) they will do as good, or way better, while ignoring a significant chance to some sort of bad effect (mostly getting a perils). If an experienced DH player has any comments on this, I'd appreciate it!