This war thing completely depends on server players. Yes, players' mentality in participating war plays a major role role here. Before the starting of war,most of the MCs think that it is definite lose, so they decide to log their elf character and take part in the other side. The skills of the classes are really controversial but I don't want to start with it. Strategy with team cooperation is always proved to be the key of success.
P.S: I saw in many threads that wardens are the reason behind the win of sentinels. IMO not focusing them will be smart move. But but but .......HIT