First of all, there is this very informative thread here from omlech, a mass info thread that should answer most of your questions... check it out!
For some of you that might be a bit much to read, so here's a nice article from a fansite which compares GW2 to Aion:
Guild Wars 2 does it different
The original GW already had such ‘dynamic events’ which were triggered when the player came within a specific distance from the NPC that offered them. Rift has them as well, in a bigger scale too, since its world is not instanced as GW’s. However, Guild Wars 2 has them in such an extent and degree that has never existed in a game before. The first reviews and impressions indicate that it’s done quite a good job with them too!2.) Repeatable quests & ActivitiesThe reason behind this misbehavior is that Guild Wars 2 does not have a Quest Log! I know, this sounds utterly dumb and incredible. Truth is... it does not need one. Let me explain. ...
... Guild Wars 2 does not break away from this rule: it (will) include ‘repeatable quests’, however neither their purpose nor their essence is going to be about grind. In the contrary, their rewards will be either titles, or skins, or dyes, or other kinds of cosmetic ones – things which do not make one player better than another by improving their stats or gear. ...3.) Dungeons & Loot... Repeatable quests do exist in GW2, true, but the game does not ‘force’ you to do them. Having the ability to choose is the defining factor here. ...
4.) Holy Trinity... Dungeons in Guild Wars 2 are like everything else in the game: fun. This involves and implies the factor ‘rewarding’. If you take the trouble and spend your time, you shall be rewarded for it. All the party members will get something for their effort – and not something useless but an item fitting to their class and character. Every time. Invariably. Do not forget the rule we mentioned above though: rewards are of aesthetic nature, proofs & trophies to show to all that you are the masters of this dungeon. ...
5.) Traits System & Money Sinks... However, as soon as we learn to play as members of a group, reacting to each situation in a way that complements and enhances the action of our comrades… As soon as each one of us learns to play right their triple role… As soon as we realize that GW2 is a new and different MMO than those we’re used to playing, we will love it as we’ve loved the original one. ...
6.) Death Penalty vs. Armor Durability
7.) Mentoring vs. Side-kick... each time you get killed, a piece of your armor gets damaged. When every piece of your armor is damaged, your next death is going to break a random one of them and you’ll have to travel back to town in order to get it repaired… by paying a small sum of gold...
8.) WvWvW vs. Siege... The difference of Guild Wars 2 on this part is that, as the side-kick system not just allows but also exhorts the players to return to low level areas (by doing the same quests with our low level friends and rewarding grouping with them), the available content is basically growing larger day after day: new content is added every 5 levels approximately while all the previous one remains available and contributory! This is pure magic...
9.) Queues vs. Server Overflow mechanic... about sPvP: All participating players are ‘automatically’ raised to level 80 (cap) and equipped with PvP gear. What does “automatically” mean? That as soon as we travel to the Mists – imagine them as the preparation grounds before entering some PvP game – we become leveled to 80: all our skills and traits are unlocked and in our disposal to create the build we feel most satisfied with. There is no cost to re-spec, so experimentation is greatly encouraged leading eventually to deciding which build(s) best suit us, so we can plan our PvE development accordingly. Additionally, special NPCs offer all the required equipment to us, FOR FREE, so we can dress up with the gear of our liking: armor, weapons, enchantments (runes, etc), anything we can imagine and desire is within our grasp. For free!
One of ArenaNet's innovations, which caused quite a wave of enthused reactions when it was announced, was the overflow servers. What is that exactly? It is the company's answer to the problem of waiting queues. Or, in any case, it aspires to be. When some player tries to connect to the game and the server of choice is full at that point, the game asks them if they wish to be placed to one of the overflow servers until a spot is available on the server proper. For as long the player resides in that 'parallel universe', they have access to the exact same PvE content they'd have in their own world, progress the same - in their quests as well as in their personal story, or in anything else they decide to play through.I cut out the "almost properly" he mentions after that quote, because grouping with friends worked well in BWE2.From what we've seen so far (after 2 BWEs) from this system, some initial conclusions have been drawn. First of all, it works! Instead of sitting there in front of your monitor, idle and irritated, counting down from ten thousand something, you get in the game right away and play properly.
10.) Alternate reality vs. Game World – the ‘Extended Experience’
11.) End Content & Epilogue
Why not run one of the "smaller" dungeons, such as the Ascalonian Catacombs? Excuse me, what was that? They're not for my level? Well, if you did say that (did you, really?) you need to read again about the sidekick system of GW2. And, thus, keep in mind that even in lower level instances and areas I will still enjoy the challenge and the loot that match my level.
for the ones of you who need more information, check out Anets blogposts and the GW2 homepage. Furthermore there are some very old threads from myself too.
Dynamic Events Overview
Personal Story Overview
Eric Flannum Answers More of Your Dynamic Event Questions
Colin Johanson Answers Your Dynamic Event Questions