Changes to be Made...

There's nothing quite like realizing a part of the game works, but the way you've explained it is bad. An example: High Explosive. Currently the rules explain the High Explosive trait as follows: Divide the weapon's Effect between the initial target, and 1 or 2 additional targets, adding any remainders to the initial target. Keeping in mind that the effect should be to spread the attack's effect perpendicular to the original target, it's bad. It's bad because you should never require people playing a game to divide, even though it's a very simple operation. Dividing the attack seems like it's being watered down, and blunted. Where a Rocket Pod with an Effect of 3 might be thought of as a mighty blast, it's more of a tepid slap because instead of those three points of effect destroying a system they're going to cause light damage to three systems. Now, does this whole scheme need changing? Maybe. Does the explanation in the rules and its presentation on the cards need changing? Yes!

Here's the notion for the change, to be accompanied by changes to the weapons with the high explosive trait: High Explosive adds 1 (left of target) or 2 (left and right of target) additional targets to the attack, causing one damage point to each additional target. Rocket Pod Effect is back to 1, HE2; Macro Gun Effect is set to 2, HE1; Buzz saw is set to 1, HE1, and every target affected by the attack is affected by shield breaker. I think that's a tidy way to go, with addition being psychologically more positive and easier to grok. 

A second, actual change that seems reasonable with weapons is a way to deal with the Mega Gun. As it stands it's hard to balance: Reduce the effect and it's a worse gun battery because of the slightly shorter range. Additionally,  consider that it's a relatively short-ranged weapon so the range of 3 squares isn't much of a difference either. Increase the cost and nobody notices. Take away the hard rounds trait and it's less interesting. However, downgrade the effect to 2 and add shield breaker, and it's suddenly got more character and it's more easily distinguishable from the Macro Gun and the Gun Battery. 

The Gun Battery itself could do with something interesting, and that brings me also to some issues with Shields and Crew. Notably the proportions of their Charge/Effect ratio. It occurred to me that maybe the Initiate Crew should have no charge cost, since they're young and energetic (and have a relatively underwhelming Effect), the Adherent crew keeps the Charge 1, and the Master Crew gets Charge 2 to compensate for the nigh-overwhelming Effect 3. Likewise, enabling the Shield systems to have multiple profiles, such as a Charge 0, Effect 1 would give players some interesting options. Notably an Initiate Crew with Charge 0 operating a Deflector with Charge 0 for 2 shield tokens would be the same then as using the crew for an Effect 2 Charge 1 activation. 

I think, given the Mega Gun and Macro Gun, having the Gun Battery have its Effect dialed to 1, effectively changing places with the Macro Gun, and having its Charge negated would give it its own flavour as a cheap and cheerful secondary weapon. 

To summarize:

1. HE needs to be presented as additive rather than requiring division. Macro Guns, Rocket Pods, and Buzz Saws need to be tweaked to reflect this. Armour Piercing weapons as well, now that I think of it (another case of effect being divided where it should be added). 

2. Mega Guns and Gun Batteries need to be tweaked to make them more interesting.

3. Shields (Shields, Deflectors), and Crew (Initiate, Adherent, Master) should be tweaked to balance their effect.