Posted this in WvW forum but this may be a more appropriate place.
Extra reward to the 2nd and 3rd place teams in each match for attacking the 1st place team objectives. What kind of reward, not sure, possibly: more points on the next tick, more exp, karma, gold, tokens, or all the above. This would encourage the teams to focus on lead team instead of beating on each other because the 1st place team is so much stronger in numbers. Kind of make a alliance without really being an alliance.
Of course the team who does win the match up for the week should also be rewarded for their accomplishment.