The Rotterdam battle between Kibet and Kwambai was pretty exciting. London and Chicago have had battles with a number of guys being in the mix the last 2 miles. NY more often than not is decided around mi 16-18 as everyone hammers it on 1st street. That is certainly fun to watch, but the remainder of the race is just a victory lap for the winner. And the women's race has become painfully tactical in the past few years.
I think NY's marketing strategy has been to make it seem like the all the champions are racing each other, rather than getting together the fastest guys in the world. NY was paying big bucks to guys like Ramala, Goumri and Lel at a time when there were lots younger guys coming up who were running crazy fast times.
At the end of the day, as long as you have a large competitive field, you will have a great race, pacers or not. The first half of the marathon is almost always dull because everyone is either locked in with the pacers or just jogging along without pacers.