Not hard to learn, but there is a lot to learn and it's time consuming. There's loads of free player handbooks for various systems. You need someone with the time and patience to walk you through the mechanics of the system; not everyone is a great teacher because of this.
It also requires a lot more time availability, sitting down for multi-hour long blocks with limited interruption.
A lot of the parts of forum writing like this are still present. It's a lot easier to get people to follow along and go for a major plot, and easier to resolve conflicts instead of resort to 'I'm more badass than you' arguments. You can quantify experience and ability with attributes and skill allocations. It gives room for actual in-character arguments and violence to cause pause for thought, because there's an authority above the players that (ideally) won't take sides and will let you know if you're dead, you're dead.
Honestly, because of that, you get less... I hate this word, but, edgy idiot characters who look for any way to act out, and people are a bit more polite. They're more willing to talk things out. Of course, like any game or creative exercise, there are a few in every bunch who aren't, but it's much rarer.
One of the popular systems that has most rulebooks present online is Pathfinder, there's several wikis and comparable websites that give information on how the game is run. It also happens to be my favorite to play.
Other systems are harder to find the complete rulesets for free online.