I m sorry, but are you serious now? What targets are going to hit with gimballed weapon with 1200m's speed as 2.5km, asteroid?
It is doable to engage an openly aggressive target at such ranges (
circumstances can allow it) or to start combat at such ranges with an opening volley (
I have certainly done both numerous times with NPCs) - but I believe you are also ignoring the fact that the shot speed of Frag Cannons are even slower and arguably less accurate at comparable ranges. For example: 667 m/s at 1.5km v. 1200 m/s at 1.5km results in ~2.25s of bullet flight v. 1.25s of bullet flight - on top of that the actual accuracy of the Frag cannon gets worse with range regardless of what mount you use for it because of one key point - it is a space shotgun and the pellets fired get further apart with range.
Cannons suffer from a slower refire rate but greater alpha damage, plus they have a slower shot speed making them a lesser choice in at least some regards - even with Engineering but that does not mean they are useless. If you can hit with a single shot then it will hurt.
Multi-cannons are the closest to shock cannons in terms of refire rate and accuracy but they do less burst damage.
Ultimately, Shock cannons are a compromise weapon - they offer an effective range closer to that of stock cannons/multi-cannons while offering a burst damage level comparable to that of stock frag cannons. They have auto-loader functionality as standard and offer better burst and sustained performance than engineered Cannons/Multi-cannons. Frag cannons excel at near point-blank engagements but at longer ranges they will suffer heavily both due to pellet spread and shot speed.
Are shock cannons perfect? No, but they are reasonably balanced when compared with the engineered weapon alternative options. Personally, I have a mix of ship builds using a variety of weapons - where shock cannons are concerned, I have used and do use them on various ships and find their performance more than acceptable even when considering engineered weapon options.
The problem as I see it is that there are a number of issues with player expectations regarding both ships and weapons (
comparable balancing arguments have been bouncing around these forums for ages) - in specific regards to the Shock Cannon, IMO if any particular element was improved then it would arguably be overpowered. Currently, it is a shock and awe type weapon rather than a stand and fight weapon and no other weapon really comes close to matching it in that regard - Frag Cannons lack range and accuracy, Cannons and Plasmas provide excellent alpha damage but lack in refire rate, and Multi-Cannons are perhaps an ideal compromise weapon given their ammo capacity and low penalty for missed shots.
All weapons have their positive and negative points, choice of which one(s) to outfit with is on the most part dependent on deployment circumstances and Shock Cannons do have excellent utility in hit and run use cases. Depending on the ship they would not necessarily be my first choice but that does not mean their balance is off either.
FTR the ONLY time I would even consider equipping a Frag Cannon is if I were doubtful over whether I could accurately target the opposition OR I was expecting to be in a knife fight type situation (e.g. short range/close quarters engagements). Regardless of alleged sustained damage potential, the shot speed is too low and the pellet dispersion make relying on frag cannons for mixed engagements unwise IMO.