Skills

Will you still have to go to a trainer to get skills, and, like in GW1, every trainer has different skills to teach you? And about the 5 weapon skills, will you be able to get new skills to replace them, so you can make your build more unique, or will they stay the same as the skills you had at level 1?|||The weapon skills are fixed and you can't change them for different skills. So, for example, every warrior with a sword will have the same sword skills as every other warrior with a sword, regardless of the skin of the sword. But skills are tiered, which means that you can obtain more powerful versions of each skill as you level up. There are nine different levels of power for skills at the moment, though this is still subject to change (like everything else about GW2 right now).
The weapon skills are unlocked over time, so you don't start out at level one with all five skills. As your level goes up, the lock icons on the skill bar will change to book icons, meaning that you can now get that skill by obtaining a skill book from a trainer. Skills will also drop as loot or be given as combat rewards.
There are ways to make weapons more unique to each player, however, other than through the skills. You will have choices of different weapon stats, and you will be able to assign traits to each weapon. The traits will have to be earned by completing profession challenges. We don't know anything about the mod system for weapons yet, but we know there are skins for each weapon that have different stats.|||I would also like to add that you can pre-purchase skills at a vendor even if you cannot currently use the skill. After your purchase whenever you reach the level at which the skill can be used the skill becomes unlocked automatically. I don't think these pre-purchased skills take up inventory space, unlike AION's skill tomes, but I may be wrong about that.
It it also unclear whether different skill trainers have different skills available, or all trainers have all skills, but at least in the demo the skill trainer had all tiers of currently listed skills.
To give an example of the progression involved, a level 1 in the demo started out with the first 2 weapon skills and the healing skill unlocked and could unlock the third weapon skill at level 2 or 3. It should be noted that completing the intro mission automatically levels you up to 2.|||Traits. That's the big way that you upgrade your weapon skills as you level up.