I think the fact that Oga's is the only place in DL that serves alcohol will have a disproportionate effect as well. I think the Cantina is the perfect size theming wise. Practically, increasing its size would have a proportional impact on throughput, but it'd still be just as crowded, just less time waiting. The maximum occupancy of Oga's is 276. For comparison, Hollywood Brown Derby is 272, but the capacity is not calculated the same because HBD is a 100% sit-down restaurant and requires more square footage per person. It'd be far easier to cut the maximum time spent in the Cantina to 25-30 minutes to boost throughput. Does anybody need 45 minutes to finish a drink or two? Granted not all of that time is spent drinking, and I think Disney should, in the short-term, make the process more efficient. For example, order your drinks ahead of time and have them ready when you step foot in the door.
Call me crazy but I love spending time in the more immersive queues. They also soak up a ton of capacity, which is a good thing when it comes to lines for other things.
I think DHS will have less of a problem due to the fact that alcohol is already served elsewhere in the park. If Disney made efficiencies and cut the maximum time spent in the Cantina, they could cut wait times substantially.