Just played some Jedi Outcast, Academy, and Battlefront 1 to remind myself of the old days. Fun times.
The Rhen Var levels are far more challenging for the Rebels than the Empire; aside from the fact that the Empire gets an AT-AT in one of them, the other level has heights and peaks that are easily accessible by Dark Troopers, but Rebels have to climb them the old-fashioned way, making it harder for them to fight their way through. I beat them well enough as the Rebels, but it wasn't a total massacre like I would do as the Imperials, where it got so funny that I'd even disable their last command post while their army still has 100 men, only for them to get gunned down to zero because they can't respawn. Rhen Var is a well-enough battle as the Rebels, I took down at least 3 AT-ATs, but as the Imperials, it's a massacre.
I'd like to think that the mission to Alzoc III in Jedi Outcast takes place after Desann's defeat. Kyle is with Jan, but he already has his lightsaber and Force powers, even though he doesn't have all his upgrades. I suppose they had to nerf him a bit so that the lone Dark Jedi at the end is somewhat challenging.
As for Jedi Academy's opening levels, I suppose a lot of people complained about the maze-like levels in JK2's first half and the Nar Shaddaa levels where Rodian snipers took potshots at you with disintegration rifles; Jedi Academy's opening levels are a breeze. But they still had their challenging bits, like when your ship crashes and some sand worm is stalking you; no lightsaber or gunning down bad guys there, you just have to be really fast. Or the Corellian level where you have to be careful about platforming so you don't fall off the train. Although the two Tatooine levels do make you feel like slicing down people is a 9-5 job for a Jedi. Almost like a Dynasty Warriors game where you cut down hordes of enemies.
I remember a friend of mine who was so angry at Rosh he's never played the Light Side ending of the game. He always opts to kill Rosh when he got the chance.