Welcome to the game. I hope you enjoy your time here. The community might seem a bit rough around the edges, but people are usually nice once you get to know them.
As for your class picks, I think it might be wise to stay clear of Shadow Warrior. They all have decent specs, but this is a very competitive game, so decent specs are sometimes not enough. Also, currently there's quite a lot of them and not much demand for the class.
Tanks on the other hand are always in demand, but only when they use Sword & Shield. There's already loads of discussions on them so i recommend visiting the faction sub-forums and just looking for the class tags in the titles (Kotbs = knight; IB = ironbreaker; SM = swordmaster).
If you pick a tank remember that realistically you will be doing more utility than dps. No one except small-scale teams really want 2h tanks.
If you do want to go DD on order, the best classes are Bright Wizard and Slayer, followed (at some distance) by White Lion.
As a new player, I would recommend starting with a ranged class, until you get to hang with the game rules and tactics (don't worry, almost everyone here has 2+ high level toons, leveling is not too hard). It's not mandatory though; a tank will be fine as well.
Some other general tips:
- join a guild; this is a community-heavy game, you need people to do stuff with; usually guilds advertise on LFG channel (/5) but you can also search for guilds using the in-game menu (just open the guilds panel). Pro-tip: First # in the guild table header orders the list by online players
- whenever in a RvR zone or in a SC, pick up the repeatable quest. Besides the XP, these are a good way of making money as well.
- the ideal leveling path is reaching Renown Rank 50+ before you reach max level. This is actually not hard to do, with the use of XP scrolls you can buy form any Quartermaster in any warcamp (these lower your XP intake by 75%). The reasoning is that once you get to level 40, you will go straight to vanquisher medallions/gear from RvR
- when in RvR below 40, you get a buff called Bolster which increases your stats to make up for your low level. In order for this buff to be is efficient as possible, you should always be wearing the most up to date gear available. Visit the gear vendors in altdorf regularly
- Around level 37-38 you can start 3 epic quest chains in each T4 zone respectively, which all give very good weapons by the end. Depending on classes, these are mostly soloable. You can find detailed links to all of them and how to complete them here:
https://wiki.returnofreckoning.com/Epic_Quests (notice: link to see rewards is a bit buggy, common practice is to complete all of them to the gear part and then decide which pieces of gear you want)
- someone has been very nice and made a cheat sheet with useful links about the game, you can find it here:
viewtopic.php?f=113&t=40739
- but besides that you can generally also find useful information at the beginner's sub-forums, here:
viewforum.php?f=113
Let me know here or in a private message if you have any more questions.