I only just saw this thread so I'll answer the questions in order:
1. Since you started playing, what has been your favorite Quest line?
Main story line. When I take a new character through it I feel very nostalgic for the time when I played with gsch before the game's release back around Christmas 2013, oh the hours spent in the tutorial looking for motifs lol
2. What has been your favorite class overall, so far, in your gameplay?
My main is a Mag Sorc, love all the aoe, not a big fan of pets but I use them occasionally. Would like to learn how to heal and I'm levelling a Warden, and will start a Templar next.
3. Which Guild or Group do you wish there would be more content for?
Undaunted maybe, seems hardest to level, I need to jump into more of the guild runs to level it up. I'd like more Mages' guild story content.
4. If you could change 1 thing on/about your favorite Toon (whether it be race, class, choices made in quests, involvement or the lack thereof in some aspect of the game, etc.), what would you change?And why?
Happy with everything on my main toon, but as for involvement or lack of in some aspect of the game - I would like to start doing some dungeons.
5. Is there an event you wish would be regularly scheduled? What event is that? When would you like to lead or participate in these events?
I'd like to join in with any groups teaching dungeons that might go a little more slowly and give the odd tip here and there about what to expect before a difficult boss fight.
6. What do you think about the new DLC: Clockwork City?
I love it! Currently running around proudly in game with the title 'Hero of Clockwork City'. I love the Dwemer style, the precusor quest, the new little pet and just the whole feel of the zone.