Lead author on the deletion paper here. Thanks for the feedback! I agree it would be cool to talk about the Ent APIs some more; they have a lot of obvious and less-obvious benefits. (For example, we are only able to add deletion constraints to Ents as described in the paper because the Ent specification language is expressive enough to do it.)
The real part of the conference is the bit in between the talks.
(Fun fact, the first conference I went to had like five coffee breaks per day, and I got a coffee at every break and complained to someone at dinner that there was too much coffee and not enough talking. They explained it to me quickly enough!)