I love both games (although in both I prefer the 1st edition).
Both are going to be tough to get under 3hrs in my view, at least initially, although it should be possible with repeat plays.
I prefer games greatly rewarding experience, and if a new player has any real chance of winning against experienced players to me that's a big flaw in a game. A new player has some chance of winning in both, but not a great deal - in my opinion Mare nostrum is more harsh on newer players because of foreseeing the game end, but there's not a lot in it.
In summary, they are both great games, but both do have some legitimate issues with both factors that concern you.
I agree a game that a beginner can play as well as an expert is not a good game, but some games give enough space to a beginner that though they won't win, they can at least have fun on their own terms. I think you answered in that spirit, so thank you.