It takes at least 6 months of constant grinding to get an able self sufficient character that can PK and make money. Unlike other MMO's where you have instances to raid this game has absolutely no raiding. Wildy is where everyone goes off to for some sense of excitement. Honestly it takes 6 months just to get a decent character. Forget hitting max stats on any of the skills. You would need to play at least 8-12 hours a day for a year or two to hit max stats on any of the skills.
Yes there are 20,000+ items, but only maybe 500 of them are actually useful. That and the economy of RuneScape is absolutely horrible. Everything is incredibly overpriced.
With that the worst part about RuneScape is the absolutely terrible community. In every single MMORPG I have ever played I have had lots of help whether it was with a quest or a small donation. In WoW alone a friend on GameFAQs gave me 10G for my starting character. In RuneScape I never ever in my life got even a single piece of gold or even an item or even any help. Unless your in a high end guild you'll never get any help in RuneScape ever.
With that let me go onto the graphics. Look at some free games like Gunbound, Trickster, and Maple Story. They all have at least 32-bit era graphics. RuneScape has Sega Mastersystem like graphics running on Java. Honestly Jagex with all the money they're making could EASILY make a under 100MB. RuneScape client that had some respectable graphics that could also easily run on a computer with 64MB. RAM and 64MB. video-card.
Finally the worst part about RuneScape is if you don't like pk'ing the whole game is a waste of time for you. There are no endgame dungeons or any particular thing to do.