Firstly, I will say I am by no where near Rogues pk'ing ability, or have his knowledge, in the pk department I am extremely average.
-What would be the first level you would say a wood elf could comfortably sit at to start pking?
I didn't really start pk'ing (to a point where I was comfortable) until I got my COW. I started once I got my treant and had sunray+thorns. But just found that I was slightly too frail to really win battles. However, once I hit lv 40. I found it was much better now.
With PK also, depending on who I would be fighting, would obviously depend how i'd go about it. Which herbs I would collect - which COW to get also.
-How hard is transmute to metal to perfect if I REALLY concentrated on it? Has anyone ever took the "never blow up objects" edge yet?
Never tried to get it up at all. Just really transmuted everything I could, and everything for other people. (Had my druid pre edge)
-Weapon damage seems neglegible... would it be better to find nodrop maces or use exotics instead of just anything.. to keep parry?
I usually tried to use exotics - There is a certain exotic I like using, it poisons. So adding poison onto thornheart and your normal damage is just a nice little add on if they get away.
-Do your sups take a large hit outside of wilderness? Are druids affected that much by fighting in a city let's say like a ranger would?
I found actually, my druid to do a lot better than I thought he would in the city. I could solo raid Tribunal (no opposition) at lv 38. Maybe having to rest up mana once or twice depending how I was going. Some supplications can't be used in certain areas like Rogue said but also, you can always set a nice trap for your escape with briars and wildgrowth (or whatever its called)
-I rarely see heros using fireseeds... and I don't want to be a cookie cutter druid with sunray sunray sunray... at hero.. what do thorns do on average for damage?
Thorns was my favourite actually - with a nice set of offensive herbs I was dealing >>> ANNHI to most people. As Rogue said also, fireseed was very random with damage, so not overly reliable.
Pretty much to sum up. Once I got a good list of which herbs where, took the time to prepare to raid/pk certain people, went and gathered the correct COW against them. One on One, unless they were insane damage dealers I was coming out on top. Generally anyway.