I haven't had any issues killing elites solo. The fights can often be close. This is the problem with the Jedi Knight/Sith Warrior being underpowered. I found fighting with my knight against elites to be much more difficult. I basically never even used heals (when available) and still thoroughly beat elites more easily than my knight. HELL, the one time I did use heals on my companion both of us died because it used all my energy. I was also wildly unready and throwing a stealth class into melee distance from a boss to BEGIN with is just cruel of Bioware. The trouble with the Knight/Warrior is I'm unsure what you would change to make them more viable against elites. Oh, well, I'm no game developer.
I ended up getting my smuggler to 17, shadow to 21 (woulda been higher but hit some fucking bug that made the character literally impossible to play - if I loaded him up swtor.exe would max out my available memory and basically do everything but crash my PC), bounty hunter to 10, and Jedi Knight to 16. I've definitely decided on playing scoundrel as my main republic character and an assassin as my imperial. I've wanted to go shadow all this time but the bug made me try the imperial version of the consular and I found the story, evil version of his abilities, and starter world enemies more engaging. Smuggler became a much more enticing option when I realized scoundrels don't have to use that ridiculous cover system. Smuggler over imperial agent because shotgunning someone in the back is pretty great. I understand both of your disappointment over the imperial dark side stuff. I'm likely going to make my assassin light side.
I gave space combat a more thorough go about an hour ago after wisely remembering to outfit my ship with the level 1 mods. It's very simple but VERY addictive and basically got my smuggler most of the way through almost all of 17 much quicker than questing. To balance that out, the quests ran out pretty fast which makes me sad, but I suppose more come up after the next world. Without buying the level 1 ship mods, the quests (other than the starter one) for space combat were a lesson in being unable to do the impossible. The game could certainly have been more forthcoming with the necessity to buy these upgrades, which basically double your damage, missile capacity, and give a regenerating shield. I would say my only disappointment with the space combat is the music composer didn't match the quality of space battle music (video games and movies both) of prior iterations of the series.
Also, as far as I know - there are items later that flat out require you to be dark or light side. I happened upon a light side vendor in the Republic Fleet but only browsed through it once I realized I was 2500 lightside points away from anything, let alone 10 levels away.
I loved how there was a tutorial tip at twenty, telling me to save credits for my speeder at 25 when they're so cheap (8k at 25). Maybe the skill is expensive?
I want to play more but I've experienced everything that's viable before the 1AM est cut off so I suppose I'm done. I don't think I've ever put this many hours into a beta. Frankly I'm glad my shadow broke, so I can't type /played.
Did you finish chapter one by level 25? My Shadow got bugged briefly after I finished the last story quest in Taris and I never got the opportunity to see if that ended Chapter one. I'm guessing Nar Shadda is the end of chapter one, though.