Graphics don't make a game, everyone should know that...
Just to clarify, I've just recently got off the game and am not dwelling on past experiences to review this game, so I won't be referencing things such as 'bots' as they are practically non-existent, now. This leads to my first point, the creators 'Jagex' are constantly updating the game with patches and minor updates to keep little things (Ex: The UI) fresh, and even large updates to help with gameplay (Ex: Quest and area additions/changes or the 'Bot-Nuke' in October).
Past that; you have to have the right mindset to play this game. There's no way you'll like this game if you don't expect to grind your skills. But the amount of skills you're able to level up keeps levelling up your skills fresh and different. Now you might be thinking 'Oh no! Grinding is bad!', well look at World of Warcraft. I'm not sure if you've gotten someone capped at 60, then 70, then 80, then 85 before the XP to level was reduced, but that also involved a lot of grinding and so did the professions. Even more so that the dungeon finder just turns the game into a pathetic dungeon grind game, but that's another review on its own; I'm just providing a counter-example. The combat skills consist of Attack (Increases chance to hit and makes you able to wield better weapons when levelled), Strength (Increases the amount of damage dealt), Defence (Increases damage reduction from melee and ranged attacks and makes you able to wield better armor), Constitution (Your hitpoints), Summoning (Grants the ability to summon familiars to boost stats and attack enemies) Ranged and Magic. All of these can be levelled up on your character and can be used at any time. There's no specific 'class' system that you need to pick when you start, just level what you want to do. There are many gathering and crafting skills that you have access to from the get-go and don't need to specify a select few to pick (Some of the skills are limited to Runescape's pay to play platform, but hey! They have to make money somehow...) and can be levelled up when you feel fit.
Quests are what you'd expect, quests. But they're not like quests in any other MMO. They're not the 'Go here, kill x number of creatures, come back for a reward' or 'Get this item and come back for a reward', no. These are quests that you have to devout as little as five minutes to several hours to complete. Why do the quests? You unlock more content when you complete certain quests. Often the completion of quests will unlock new zones, grant you XP in certain skills, or even just the ability to wield certain weapons. There are only about 20-30 quests for the free to play platform and the number increases to 200+ on the pay to play platform.
There's also many different things within the game to grab your attention and possibly reward you with rare items (Ex: Clue Scrolls which act as mini-quests with a huge range of items for rewards when completed).
And really, I haven't mentioned the sense of accomplishment that comes with this game. When you max a skill out, it feels good. It takes a lot of mental focus and dedication for some of the many skills and to max those out really makes you feel like you're ontop of the world.
A lot of people will cry about is the death penalty. Now, this is one thing that I hate about current MMOs, the fact they're carebear. In World Of Warcraft, your item durability goes down in which you have to pay money to repair, in Guild Wars, you have a damage reduction in the instance... In Runescape, you have some items that are automatically protected (In PvE; like quest items and some equipped items), but the rest is lost when you die and must be picked up within 5 minutes of your death. Not only does this make the player cautious and up an ante when you go into dangerous areas, but it's even less forgiving in PvP. When you die in PvP, you lose every item except for 3 of them. Considering people are use to just 'releasing spirit', this changes everything and actually makes you put something on the line in the hopes that you kill your opponent to get his gear.
Now to the PvP. People will say that it's just 'point, click and wait' PvP, but do that and you're dead and you've lost everything. It requires to be one step ahead of your opponent in order to combat his loadout as many players will carry 2 sets of armor in order to balance the 'class triangle' (Warriors are strong against archers, archers are strong against mages, and mages are strong against warriors), plus the drinking of specific potions, cures, changing of prayers, and knowing when to switch your gear and use special attacks on your opponent are all reasons why the PvP is fun. And with the recent readdition of the Wilderness (An open world PvP area), it's all the more to have fun AND make money while you PvP and loot your dead opponent's items.
Bottom line;
Addicting gameplay to come back to when everything else is boring you.
Spend some time with it, don't knock it until you get into the meat and potatoes of content.