There's always a discussion on whether PvE should be balanced or not. The reality is yes, it should, whether because certain playstyle is too good that the alternatives are comparatively worse, or if the other options are just so bad that a meta forms around not playing in other ways. And worse yet, is if the playstyle completely remove fun from the other players (such as the GL). 

Battle focus on the tactical is what many and I consider to be the former: It is performing far above its weight class as a gear perk, and in my opinion should be altered to not make the others obsolete, or less desirably placed into a different column. 

Other perks in the column

Improved efficiency: the tacticals equipment refund skill. While equip refund is always a great choice, this specific one is hindered by the fact that it is tied directly to the cool down of auspex. I dont have the cool down time of auspex memorized, but it's probably between 2 to 3 minutes, or 120 to 180 seconds. Either way, it is inferior to other classes' equivalent. (in my opinion it should just be changed to be the same as consecutive execution). 

Precise calibration: enemies take 75% more damage from auspex but radius is reduced by 25%. This is a very strong perk on paper with a seemingly small draw back. A bit boring, but serviceable. A very good modifier esp if you are confident in your auspex precision. 

Why is battle focus considered OP? 

The reality of the situation is that the game's rather confusing damage model, specifically on the bolt weapons, start to make sense when you realize when auspex is active, many enemies drop like flies. It is not at all strange to see warriors or rubricae die within 7 to 8 bolter rounds, which, considering how readily available ammo is for these weapons, is extremely efficient. I'm not a fan of this model either, but it is what it is. 

Of course that's not the focus of the discussion here. What doesn't change however is the fact that auspex is limited by its considerable cooldown (at least, in a vacuum). Battlefocus essentially removes this barrier completely, while ensuring you can still have at the bare minimum a 50% damage bonus, which you can get up to at most 2.1x or 210% (assuming of course that the wiki articles formula is still up to date). Having the ability to potentially keep your active ability with a 100% uptime is immensely overpowered, even more so since the auspex is considered a team wide buff as it affects nearly all damage dealt to a affect enemies. 

How this perk managed to duck under the radar for so long is actually possibly because melee weapons used to be very mediocre, and ranged damage was king. Now that we have access to improved block weapons, which are some of the most power tools we have access to, battlefocus became a no Brainer for any tactical builds. 

Proposals for a less brain dead battlefocus, aside from its complete removal

There are some ways that I think battle focus can be made both more interesting and less brain dead. While I'm not a proponent for it's complete removal, that is indeed an option, but again maybe we shouldn't be too drastic about making that decision. 

1) consider adding a cool down for battlefocus like intimidating aura. This is a quick and lazy way to make battlefocus harder to maintain 100% upkeep. I don't think this is at all a good idea because depending on how long the cool down is it could either be completely meaningless as auspex can be modified to have a longer active time. If the cool down is too short, like intimidating aura, it'd be a non-nerf. If it has a long cool down, it will disproportionately neuter specific auspex build that doesnt have a long active time. I do not recommend this change. 

2) consider making the auspex effect last half as long as the active ability. Again, this might not be an ideal move as this will disproportionately affect auspex build that doesn't have a long active time. On the other hand it might not matter at all as enemies affect by auspex tend to die well before auspex wear out, and auspex build with longer active time may essentially be unaffected. 

3) neuter the effect of battle focus to not be affected by your auspex perks, so it can only be 50% extra damage. This is a simple solution that I think is probably fine for the most part, but I will admit I'm not a fan of a perk not having any interaction with other perks. Admittedly, the ability to have your auspex active pretty much on demand is probably going to be very strong regardless and that in itself provide plenty of synergy with, well, anything

4) limit the usage of battle focus for only during specific times. I'm not at all sure if this is going to be helpful for holding battle focus back. Let's say it can only be activated when auspex is up, then you'll get a situation where tacticals would refuse to use their auspex (and honestly I personally hardly use auspex when I'm running battle focus anyway, because there's often no reason to). If we invert that and make it so you can only use battle focus when auspex is on cool down, it might cause a reversal issue where people would throw auspex at random things so they can get value out of battle focus. I don't know if that would be the case, but who knows. 

5) require more inputs to activate battle focus. This is only going to disproportionately affect balanced weapon IMO. Fencing and block likely will be relatively unaffected if the parry requirement is too low, and balanced would be decimated if the requirements are too high. I don't know how well this will work. 

6) completely remove battle focus. Not a fan of this because battle focus is a cool perk in theory, just implemented poorly. 

Conclusions

In the age of modern gaming, it is easy to call any attempt of balancing games a 'spread sheet balance', or a 'Alexis balance', which is used to indicate a developers lack of understanding of how their game works, and their attempts to change things for the wrong reason (which frequently results in a reduction of how player skills can be expressed). It is easy to dismiss any changes that seemingly don't benefit the players as 'nerfing fun', but at the same time we have to try to maintain a critical eye on how and why some perks or weapons tend to become a staple on most loadouts on the highest difficulty level, and what tends to not at any given difficulty. I can say with near 100% confidence that every tactical playing on absolute level is running battle focus. Battle focus is so grossly overtuned that having it and not is probably what sets him apart from other classes. What was meant to be a perk to make him a more competent melee fighter ends up making him the class with the highest burst and sustained dps, whether in melee or ranged. This perk alone can possibly allow a half way decent tactical player to clear the highest difficulty on his own. The goal of this post is not to 'ruin fun' for everyone, but to provide an objective (as much as I can) observation on why battle focus is essentially the best in slot perk for not just this column, but tactical as a whole. There is no build where this perk doesn't benefit, whereas the other two options have very specific conditions to meet or have noticeable trade offs. Battle focus demands very little in the way of skill, while provides extremely high rewards (4 shotting a lictor, anyone?). If an action is relatively easy to perform, it should not have an immense benefit. This is a very simple concept that saber seems to miss at times. Hopefully others can agree and talk about this issue.