This morning touching the complication was opening just to my day/week list view, but now it opens to my current appointment details. I think the behavior appears to be that it takes you to the list view if you do not have an appointment happening now. If you do have an appointment happening now, it pauses at the list view before opening the appointment details. I'm okay with that, but yes it would be nice to have an option there.
So far it seems great! I use Fantastical with multiple Exchange and Google calendars, so I like that it puts a colored dot next to the complication so I can tell which calendar the appointment is on. I thought Fantastical was one of the quicker non-native apps before, but it's even faster now that it is native. I was really glad to see this update, because Fantastical is one of my most important and most used Watch apps. Now that it offers complications, my watch faces just improved 1000%
Sean