Well, I played a 6 point battle level engagement against the shadows - 3 battlecrabs with fighters (so actually more than 6 points for the shadows) and it came out almost dead even, it was a narrow victory for the EA, so I really think the big guys are proably good as is. I think the problems come at low PLs where the main problem I see with the shadows is that they have a very small selection of ships to use. no variety.
Perhaps we cold come up with variant hunters and variant scouts to broaden the base so to speak like a raid level hunter and a skirmish level scout.
so a raid-level hunter - might have a weaker, turreted, longer range gun, say 1/3 less DP, same speed and hull. no fighter carrying capability.
a skirmish level scout - thats not actually a scout. so lose the scout ability. like an escort kind of vessel. give it a minibeam version of the scout gun, same arc/range, a bit faster, same DP, down to a hull 4 and 1 weaker stealth.
maybe its the lack of options the shadows are missing.