Have watched all 4 races too and finally for the first part of race 4 we got a proper race but the margins are so fine in these races that it doesn't take much to get some distance between the boats and once that happens, the risk of error or a penalty being incurred drops dramatically and its pretty much all over for the trailing boat. This then doesn't make it great as a spectacle unfortunately.
The margin in time difference might be low but it looks like a long way on the water. Its a bit like two F1 cars racing on an oval track. A 10second difference between the two would look a bit silly. We've got something pretty similar to that in the LV and AC. IMHO something needs to change in this regard to make it a bit more appealing.