You all seem to ignore Righteous fury versus hordes. Have I missed something, is RF not rolled vs hordes?
A heavy bolter doing four hits will cause 12 d10 to be rolled, getting an average of 1.2 RFs. For this type of attack you're quite unlikely to not get a RF in the damage roll. This makes it necessary to roll all the damage dice even if the min dam exceeds the soak. Sad but true. I guess you could ignore RF vs hordes but that is actually quite a hit to player power vs hordes.
Since I'm running with the RF house rule (+1d10 per RF rolled, which will usually be pointless since the soak is already breached in most cases) I have instead just stated that each RF rolled vs hordes means one additional hit (after multipliers). Still, a lot of dicerolling is required, my players seemed to be ok with it though. We've also ruled that RF is autoconfirmed vs all opponents with DW training which also reduces the dicerolling.
You have been misreading the RF rules, I'm afraid. Righteous Fury doesn't mean an additional hit is scored. It just means that the damage of the hit you are resolving gets increased. Which in turn means that once the damage rolled by the PC exceeds the hordes soak, it doesn't matter anymore. It doesn't matter if 1 damage point gets through or 1000. Whether you roll RF or not the magnitude damage to hordes always stays the same.
It seems to me that the RAW does imply RF is a full extra hit, with all the modifiers and other trappings of that. However, our group instantly found that continuing our old rule from DH of just considering them extra die of damage on the initial hit works much better by giving a better chance to overcome Toughness/armor of big enemies and also has no impact on interations with horde or other mechanics due to having to calculate or figure out where extra hits came from.
Hordes, if run RAW, require an absolutely insane amount of rolling that very rarely will change the outcome. Our group also adopted a number of the suggestions found here through our experiances.
So, to speed up your horde play, here's a few steps detailed in one list on how to fix things:
#1 Work out the minimum damage of your weapon and find out if it will cause a wound to the horde. If so, there is no reason to roll damage at all using the sensable version of RF.
#2 Have blast weapons automatically cause damage equal to their blast rating to the horde. Even the lowly frag grenade will still cause a wound to the toughest hordling in the base book (Tau Fire Warrior) with an AVERAGE roll. If it's the most common outcome, why bother rolling 6 times to see if you hit and then roll 6 damages to see if you cause a wound? This is particularly true since these blast weapons are almost all the sort of thing DESIGNED to kill large groups of fleshy targets that make up the hordes, and yet due to the low to non existant flat bonuses to damage most of them have they end up being the least likely. Makes no sense, so just skip the hassle of rolling to save time AND make the outcome make more sense.
These two simple changes speed things up dramatically, and really do little to change the outcome. The only reasons I can see to not use them are if you're using the RF rules where it grants a full extra hit, which has quite an impact on horde battles, or if your players are absolute sticklers for rolling out the small chance that your explosive weapons don't blow people up. I think after a couple horde fight's they'll change thier stance.
Sorry Assault guys, no new house rules to make melee rock against hordes. But then again, WW1 showed pretty well that machine guns and explosives were the most effective ways of dealing with massed infantry like hordes. One guy with a blade really doesn't do much in that situaition.