I know Verain did the math a while back and decided that range cap. is BiS for BLC. I have a cap. comparison I've been holding for a while now, I figure I'll put it here and hear your thoughts on it. The main thing is that I don't think range cap. is optimal for any blasters unless you feel like you need the extra range. Freq. cap. seems BiS in almost all circumstances.
Engineering crewmember – Yuun/2V-R8.
Increased hull damage (T5 upgrade), power to weapons.
Where relevant, increased crit chance is taken instead of arc/power consumption reduction.
On HLC, shield piercing was taken instead of increased hull damage. If shield damage is taken instead of hull damage as the T5 upgrade, freq./range cap. are unaffected. Damage cap. difference is as follows:
Damage cap. is trickier since it depends on the target (shields or hull). Range can beat damage cap. in some cases, but usually damage will come out on top. For example (BLC again), at 3000m the target needs 50% evasion or more for range to beat damage at hull damage. At 4000m range is better than damage at hull damage for any target, but at 2000m the target needs more than 76% evasion. In most cases (since you want to fire BLC as close as possible to your target) range is of no advantage whatsoever.
The bottom line: freq. cap. is almost always highest DPS. It will always increase your DPS by the same percentage regardless of what power setting you are in, too. Damage cap. is behind to freq. in DPS always, but comes with the added benefit of higher DPSh. It will increase your DPS and DPSh more (relatively) if you fire with power not to weapons. Range cap. is generally last in the DPS line; the accuracy gain is negligible in all but edge cases for higher damage.
Freq./range cap. also benefit more from DO, since it increases base DPSh by 100%. A DO will net 76.3% DPS increase (of current, hull damage with all blasters but HLC) to a range/freq. cap. user, while only increasing the DPS of a damage cap. user by 70.9%.
So the way I see it, freq. can reduce TTK by up to ~13% (for BLC & HLC), damage can reduce TTK by up to ~7.5%, and range will rarely reduce TTK. It's worth noting that damage cap. might not reduce TTK at all (if you need 5 shots with or without it, it's effectively not there), freq. cap. will always reduce TTK (if you need 5 shots, the 5th one will always come quicker) and range cap. only reduces TTK very slightly if at all, except in fringe cases (firing on a high evasion target from max range with BLC, for example).
See comments for revised conclusions.