Now I'm not the most veteran of players, but I'll try to answer you.
1) On skills: It's surprisingly fast to level skills at first (the first skills take like ten minutes to train) but gets explosively slower as skills start taking days, weeks, and months to train. I do like the model more than standard MMO, because that means people with jobs can throw money into it and just have the practical skills to work on. There's a smarter, more mature group of players in EVE than in other MMOs, as long as you keep the right company. On stuff: It depends on what you do, really. I started off mining, refining, and trading the refined products and made a few hundred million in the first couple months of play on my own. Mining is slow and boring. On the flipside the combat stuff, solo anyways, doesn't seem to net as quick and large a profit, but then you're training comes in handy against other players as well.
2) My low-spec, 6-year old, held together by tape and with no actual battery can run EVE pretty well. It's not beautiful, but it's pretty smooth.
3) I've made a good bit of progress alone, but eventually you find people who you can work together with. Solo gameplay and group gameplay are just about two separate EVEs, in my opinion. It's kind of like bacon and pork chops. The smaller one is delicious, but it's not as big or as filling. But the pork chops are bigger, and heartier, and can still be extremely satisfying when done right (or horribly bad when not). Just to be clear, Solo gameplay is bacon and group stuff is the pork chops.
4) Like anywhere on the internet, really. But it's pretty easy to find a group of people you can tolerate and blow up the ones you can't, and when you look behind the scenes it's the same general group of d-bags that try to run things (not referring to CCP...or am I? No, not originally, anyway). I know I can't go and play any MMO without having "Goon" mushroom-stamped all over the place.
5) By no means is it limited. I can't really explain what there is to do well, but there are a good few tutorials once you start that scratch the surface of the tip of the iceberg.