I actually think the faster release schedule is better because not all players want the same content or want to buy it right upon release. Since there are different types of playstyles, I think it's better to know when multiple types of content will be available rather than going one at a time. They used to release teasers that hinted at multiple upcoming packs so it isn't a new approach.
I 100% agree that they should have an active QA team both before release and as needed, after release. I don't think it should be an either/or scenario since this is a AAA gaming company with a large budget working with an established product. If anything, I'd say hire more people and keep up the pace while increasing quality.
I know that when they just release one pack at a time, there becomes a hyper focus on it and players who aren't interested in that pack get frustrated. I think it's better to give people an idea of what to expect. They are probably limited by rules around competition. I'm guessing that they have to make sure that their copyright protections are very solid before releasing information about packs.
Anyway, I like knowing about a season of different content at a time.