I have done 4 dungeons now, 3 on my engineer, 1 on my guardian.
What needs to be fixed instantly:
1) camera. Try CM on a melee class and you know what I mean. Not recommended w/o prior popping of a seasickness pill.
2) gfx effects. Other MMO's have, what GW2 desperately needs. an option to switch off unneeded gfx fireworks eg, the effects of your team mates. That would actually make it possible to know when to dodge and to see, where to move to safely.
what needs to be fixed asap:
1) Aggro. Wether the removal of the holy trinity is good or bad is debatable. Whats not debatable is that the way it was implemented has 2 huge drawbacks:
a) removal of most of the teamplay. Everyone just tanks, spanks and runs for himself. Most teamplay required is 1 guy throwing boulders or standing on a plate.
b) removal of most of the group tactics due to lack of aggro management. Ie: chaos instead of teamwork and group effort.
I doubt we get the trinity back, but anet urgenntly needs to think about fixing teamplay and aggro management.
what needs to be fixed in further addons:
As of now dungeons are no brainers. All they require is grit your teeth and spam your skillbar 100x against dumb but high hp mobs. Basically the same for trashmobs, boss ads and bosses. This also explains why dungeons in GW2 are called to easy and to hard by the same player: Their difficulty is achieved in a not challenging, cheap and no fun way.
I remember an MMO where it took the best players 5 weeks to get to the endboss of a newly released dungeon. The forums were bustling with progress reports and discussions about different tactics. Yours truly and his than top 3 guild even needed 2 months. And we went day after day, since it was fun, good loot on the way and we found a slightly faster and better way every time.
That MMO has an overall rating of just 70% on metacritic, compared to GW2's 92%. But when it comes to the dungeons it's the other way round: 60% for GW2, 92 for other MMo's.
In GW2, dungeons were done the day 5 players had the apropriate level. And a week later players grind them. Nobody ever bragged on chat about doing a dungeon in GW2 or claimed a wirldfirst in any forum...
In every other MMO dungeons are the highlight. The place were the designers put most effort and which are used to advertise and showcase.
In GW2 town design and jumping puzzles got more attentiton than the dungeons. It looks like the dungeons were added last minute before the game was released.
This and also the constant messages of exploit fixes are a clear indication, that both dungeon design and their playtesting need a lot of improvement in GW2.