Need advice - came back from a big break
As to the rerolling part, I strongly suggest you read over the new trait system first. Any old chars you have will use the old system where they unlock as you level. If you delete/make new chars then they will fall under the new system.
The new trait system: http://wiki.guildwars2.com/wiki/Trait_guide
Not much of a pve guy, but i’l try to answer. For the 2nd and 3rd question, i leave a possibility i’m wrong since i don’t do pve much.
1.Rangers can take down warriors, but it takes time and is very build reliant. Also depends if you are talking about spvp or wvw. For the reroll maybe mesmer might suit you, it has high burst damage and is able to kite pretty well.
2.As far as i know, glass cannon is the way to go in dungeons, at least for people how try to clear it fast. I usualy join a more relaxed run since my gear isn’t fully optimal for speed runs.
3.For gold farming i think it’s best to run different dungeons and paths each day for dungeon dailies and not run the same path over and over since they have diminishing returns now. Hotw p1, cof p1, TA up and forward and SE 1 and 3 are the fastest and easiest. Not sure about the rest, i only did those when i needed gold. Also, strength got nerfed so there are couple of good cheaper alternatives now too. I think Pack and scholar were mentioned to be on par with strength now.
4.The easiest way to see the real mesmer is that the clones don’t strafe or go backwards, they only go forward or stand on one spot. They also don’t jump, dodge or do any other attacks other then auto attacks.
After a while it will just be natural to see the real mesmer, just need to practice.