It didn't seem that long ago everybody was complaining Tie Swarms were to strong! Then, the world champion showed us how good the B-Wings really are and the imperial is the underdog. I tend to collect all the ships in full squads so to me the more the merrier, don't care what faction.
Rebel Aces
The empire is fun, but fun doesn't equate to amazing. If you don't enjoy tie swarm ( which I don't ) your upper level lists are a lot more limited. Which I think is an issue. Aside from a couple, rarer exceptions you see the higher end lists. The empire show up mostly, with strongest showing as tie swarm. For rebs, you have the Tri X wings, B's and X's, Han with his X's, etc. With only more solid X wings coming out as well as more varied love with their aces. Where the empire got double the Squints, which I love but I don't see any of them bringing squints to the next level. Those who love them, will love them more, those who don't, aren't missing much.
Now don't get my post wrong, I'm not saying the empire can never win or woe is me. One does seem to size up better then the other with what we know. I mean a pilot that eats stress on an already good ship ? Upgrades that lower costs of a ship ? I think the upgrades help speak the story. I'm not saying everyone flee from the empire but I can see why people would feel a little jilted.
Though for people picking one side over the other. That is just human nature, if there are two sides some people will pick on as "theirs " even if they have both. I have a small bit of rebels as well as empire but I'd say I'm firmly an Empire all the way player. I'd say it also goes with the backstory of the game to pick a side to really support, makes the games more narrative feeling.