Note: I am a currently GW2 player and like the game. Hoping to put some context around the above's comments for people who haven't played the game.
1) The game play did majorly switch between GW1 and GW2. They reimplemented the class system, created a whole new skill system and a bunch of other things. Some of this were a disappointment to me as well, as they removed the "Monk" class and you no longer had the ability to have a Main and Secondary class for each character. Beyond that though, I found the rest of the changes to be an improvement for the most part.
2&3) At any given time, you have 10 skills on your character. The first five skills are defined by what weapon combination you are currently wielding. Every Necromancer using a staff will have the same five skills. You then have a slot for a healing skill, three slots for utility skills and one slot for an elite skill. On top of this you also have a "trait" system, which modifies your skills or gives you bonuses for certain types of actions (steal HP on crit, your AoE skills get bigger, etc). I find this is where most of the customization comes into the game, while in the original GW you simply just dumped points into various stat pools to make the associated skills stronger.
It does suck that you can't move your weapon skills to different slots. Some of the skills i use far more often than others, and it would be nice to have those as one and two all the time, instead of two and four on one set of weapons and five and four on a different set of weapons. The rest of the skills (6-0) can be put on different keyboard commands though, as most people I know make "Q" their heal skill and "E' their elite skill. Overall I think that after you play awhile, you just get used to it. I constantly shift back and forth between my two weapon configurations on multiple characters and no longer have issues, but it did take awhile to learn.
4) There are two storylines, your personal story line and the "Living World Storyline". I agree about the personal storyline. After about level 40, I became rather disinterested in it. GW2 for the past year has been pushing out bi-weekly updates that push the "Living World" story forward and this one I have enjoyed immensely.
5) This is the one that I have to disagree with, unless we have very different versions of grinding. Basically anything in this game will give you XP. Craft a new item? Explore a new location? Do a jumping puzzle? Congrats, you got XP for all of that, on top of any killing that you have to do. So leveling I never felt was a grind, as I had a choice to basically do whatever I wanted in game and I would level up for doing it.
As for equipment... everything in the game is craftable. Legendary items do take a lot of grinding to acquire, but they are meant to showcase the dedication of the player. Between Karma rewards given by the vendors when you help out a location and the ability to craft equipment, I've never had to either grind or spend real money to get equipment. I've gotten so much crafting stuff just by running around and salvaging stuff that I make stuff just to throw it into the slot machine for a chance to get a precursor item.
