You are likely not really using the Rogue Toolkit as well as you could. You should be in Stealth as much as possible, you should be using CC all the time. You should be using your Defensive Cooldowns as much as possible.
Rogues, in general, aren’t designed for Mass Pulls, though they can deal with those too, to an extent. However, Stealth allows you to bypass Enemies, to sneak past them and get to your objective, so you actually have get to make an active choice of when and what to pull, unlike the other, Non-Stealth Classes.
A typical way for Rogues to do a Kill Quest is to sneak past the Mobs and Patrols, CC the bodyguards and then kill the Boss by attacking from Stealth. After that, you sneak back to safety, like a ghost. It’s a different mindset, a different approach to problem solving. Instead of just hitting things until you win, you approach things sideways.
For Solo Content, all Specs do just fine. At the moment Outlaw and Subtlety are doing more damage than Assassination, with less trouble. If you aren’t doing Group Content, you have more flexibility with Talent Choices, but going with the “Easy Mode” Talents on Icy Veins, you’ll do just fine.
You’ll want to look into some Macros, to make it easier to use certain abilities, like Sap, Blind, Distract, Gouge or your Stuns. Basically, any CC ability, or anything that has a target reticle to it, Macros will make using the much easier, faster. This will also help with changing how you think about those abilities, and you are likely to use them much more.
Have fun!