Fake Balance: A result of the game's asymmetrical factions. Although the game bills the Empire as being strong in the early game before the Rebels catch up and both sides become equal, the opposite tends to be true. Due to a number of factors apparently caused by the developers not thinking things through, the early and mid-game heavily favours the Rebels; in an unmodded Rebellion game, playing the Empire is seen as a significant handicap and most modders give the Empire a few power boosts to compensate. Notably:
Although the Empire's early capital ships dominate anything in the Rebellion's hands, it takes quite a while for fleets to really become an important factor, as the initial shipyards produce ships very, very slowly. Unless you want to take hundreds of days to build a single Star Destroyer, the player generally first needs to build numerous construction yards (which takes a while), then get those construction yards to build shipyards (which may also take a while, depending on which planet(s) you choose as your shipyard planets). In the time that it takes the players to do that, the Rebellion will almost assuredly have moved up the tech ladder and unlocked ships that can go toe-to-toe with anything the Empire has on hand (when the Rebellion unlocks Assault Frigates (which doesn't take long), the Empire's advantage in space completely disappears and it takes a long time for them to even return to even footing, let alone reclaim a marginal advantage).
Even in the early game, while the Rebels have a distinct disadvantage in capital ships, their starfighters knock the stuffing out of any Imperial ship they cross. The Empire has no effective counter until they research Lancer Frigates. And, unlike the Imperial capital ships, starfighters can be produced quickly and cheaply, even from a planet with few shipyards. A rebel fleet composed exclusively of Alliance Escort Carriers will strike terror into any Imperial's heart until the lancers start rolling off the line.
The rebels always start with Wedge Antilles, who can begin research on new starships as fast as you can get him to a shipyard; the Empire, on the other hand, does not have a research-capable character amongst its guaranteed starters. Unless you are lucky with your random character(s), the Empire will be late to the research game (potentially cripplingly late, if you're unlucky with your Recruitment missions).
The Emperor's character bonus requires him to stay idle at a base that the rebels are guaranteed to attack sometime; none of the rebel characters' inherent bonuses require them to be stationary OR idle. Made worse by the fact that conquering the base in question (Coruscant) and capturing the Emperor are two of the three victory conditions for the Rebellion, forcing the Empire to put most of their eggs in one basket.
The Empire always starts with one planet that is forcibly occupied by Imperial troops, yet is loyal to the Rebellion. This planet is something of a ticking time bomb, because it is a ripe target for a rebel Incite Uprising mission. One of the Empire's first priorities is getting a diplomat to this planet and trying to sway it to the Empire's cause (contrast with the rebels, whose diplomats will probably be spending this time recruiting valuable, neutral planets). Worse, if an uprising occurs or the Rebels succeed in freeing the planet, every other neutral world in the sector also winds up joining the rebellion.
Han's Millenium Falcon-gifted speed is a huge pain to Imperial players, as it allows him to bring a unit of insurrectionists to an Imperial-controlled, Rebel-aligned world and incite an uprising faster than the Empire can get a diplomat and/or troops there to suppress the mission and quell the discontent. Worse, if a planet falls to uprising, it takes most of the sector with it. If the Empire is really unlucky, the "target" planet will be far from any diplomats and close enough to the Rebel Base for Han to claim the entire sector long before any Imperial response can be mustered.
The fact that the Rebel base is located in the Outer Rim AND is hidden from Imperial eyes allows the Rebels to start secretly colonizing the rim long before the Empire can get a colonization fleet put together. While the Empire's production planets are easily located and targeted by the Rebels for sabotage or fleet assault, the Empire has to actually find the Rebels before it can start hindering their production. The Imperials do get one advantage in that they only have to find the rebel base once and destroy it (and it can be sabotaged), but the rebels also have the option of moving the base as many times as they like, making it very difficult for the Empire to track it down and destroy it for good).
The number of characters protected by Plot Armor varies between the two factions. On the Empire's side, only the Emperor and Vader cannot die; on the Rebellion's side, that tally includes Luke, Mon Mothma, Leia, Han, and Chewbacca. It's particularly frustrating as an Imperial player to note that it's completely impossible to permanently put any of the rebellion's best characters out of action (though injuring or capturing them can waylay them for quite a while).
Fake Balance has been detropified. Removed