ToME: the Tales of Maj'Eyal

I think Arena mode would be best off starting unlocked. It offers an avenue for experimentation for new players who are overwhelmed by the full campaign.

In fact, how about turning around the current unlock situation? Let's require a 30 wave arena win to unlock the shady arena guy in the Maj'Eyal campaign. The arena teaches a lot about tactics, so that would be a very educational unlock

Neat idea! The reverse unlock makes a lot of sense. I'd make it easier though - say do 5 fights in arena mode to unlock the shady guy.

Every player should be forced to try out Arena mode. It's immensely educational, whilst opening up new avenues of fun for the game. Many who don't like aspects of the main campaign would enjoy the arena much more.

Not sure about forcing.
Many players would not play arena mode at all and those 2 generic points are helpful.
This would create a spoiler required type situation.