The recoil spring in my WASR was either too weak from the factory or wore out too fast by the 1k mark, didn't notice it til I compared it to my Draco pistol.
So after the break in period I'd look at a stronger recoil spring, I went with a Wolff spring.
There's a few good videos on doing a 15 minute polish job on the WASR to smooth it out, not necessary as it'll eventually wear it on it's own but it's a simple and safe process.
And that's really about it, everything else was just accessories. If your has the G2 trigger like mine did it's pretty good out of the box. I did take a little off the back of my hammer to smooth it out, there's plenty of threads covering that, how to ,how much, etc. And of course, it's nothing that affects operation or reliability, and will also wear in over time.
By 'paper clip' thing in the trigger, do you mean the Shepard's Hook? If so, I'd not worry about that, won't cause a problem. Unless you plan to replace your trigger you won't know it's there.