[Sombre]

I don't think you can have 'poor diplomacy' and beat anyone who has 'good diplomacy' unless you're playing a duel. Diplomacy is by far the most important factor in MP. The number of times a clear winner has continued to win throughout the midgame, extended it into the lategame and, surprise surprise, won in the end simply due to them persuading people not to attack them is pretty staggering. Meanwhile people with 'poor diplomacy' scrap amongst themselves until they get flattened by someone who hasn't been in a vicious bloody stalemate for the past turns.