FWIW, Omega seems like the answer if the overhead for resolving inconsistencies becomes low enough such that the benefits of optimistic scheduling outweigh the costs.
[0]http://www.slideshare.net/sameertiwari33/scheduling-on-large... See slide 6.
One note on priorities a la Borg (what I think people are actually using at Google today, but I don't know to what extent Omega was merged with it after the Omega paper or if Borg currently runs as an Omega scheduler or what), is that it sometimes causes annoyance for people at Google, as the optimal priority is not always assigned to certain workloads, leading to starvation or overpreemption of things that were not given a healthy number. I believe that Mesos' work on oversubscription took concerns around this issue into consideration.
It's really fascinating to compare the architecture of Nomad vs K8s, because both claim heavy descendence from Omega + Borg. If I squint, it seems like Nomad is more of a direct implementation based on those papers. K8s more explicitly modularizes more components, which I think is why a lot of companies are jumping behind it, as they can mold it in the ways they want.