The 2 player preference of Arena players is one of the weaknesses on BGA, the reason for this is well explained by Jontia above. Like many games I prefer to play TTR what it is designed for and that is normally better reflected on BGG, which says 4 player games is most popular for TTR. It's just for strategic (minimizing risks) and speed reasons that guru's vote different. I assume the top ELO players also don't play multiplayer because they loose to much ELO if they finish 2nd out of 4 players, this could be a weakness of the ELO ranking as well. I just don't focus on it too much and play the multiplayer games I like in stead of focussing on ELO / Arena rank.
I always encourage players to set up their own tournaments with multiple players as soon as they have an idea of the time needed per player (for casual players it's about a week for this game).
I always encourage players to set up their own tournaments with multiple players as soon as they have an idea of the time needed per player (for casual players it's about a week for this game).