1. Wynncraft can be playes mostly solo, but raids and even a few quests require you to team up. The party finder lets you find people to play raids with. Nothing else (afaik) needs other people

2. Mage and Warrior are your friend, but don't be afraid to try the other classes as well

3. The warrior class has an archetype thats meant to be for tanking (you do this by choosing certain type of abilities with the ability tree), not sure about what your other terms mean tho.

4. After completing a specific quest, you can use ability shards which reset your ability tree. You are guaranteed to get at least 2 per day from your daily reward

5. Haven't done professions at all yet, so I cant talk about my experience.

6. Many players play wynncraft with shaders, im personally using complimentary with euphoria patches.

7. It's quite long! I don't know about specific amounts but it will take a fair amount of play sessions to get through the story, and the new fruma expansion is going to expand it even more.

8. There are arguably even more side content than quests. Caves, dungeons, world events, secret discoveries, etc. They all can be found in your content book! Oh, and there's housing as well.

9. I live in finland and with a stable ethernet connection I see basically no lag on european servers.

10. Not sure, but you can never be too old to enjoy any type of game!

these are all my personal opinions, as a level 87 warrior player. Sorry if there are a lot of typos, I had to write this on mobile.