I agree that some battle-packs would be pretty cool, and there are some people who would buy them. The previous non-licensed battle-packs used to go for around $15 USD a few years back for 5 figures, so I understand your rationale for 4 figs for $12. However, pretty much all of the major licensed themes have been all about the figures. I don't know the ins-and-outs of how LEGO plans stuff, but they appear to understand that there are many people who are out there to collect the figs and will pay a lot of money for a large set with one unique figure in it. I have to imagine that figures are also rather expensive to produce since they have a lot more detail/painting than normal bricks. So, from a business perspective, it makes sense to me to spread the figures out as much as possible. I'm speculating that even though they would probably sell a ton of battle packs, the profit margin on a battle-pack isn't nearly as good as getting someone to buy a regular set.
All that being said, I think they are trying to appease the army-builders by offering sets like the Mirkwood Elf Army and the Uruk-hai army pack where you get a decent number of figures along with some regular bricks because there are tons of people who will stock-pile them to get a bunch of army-builder type figs, but you're still buying a $30 set. This is all speculation on my part, so I could be totally wrong.
As far as the sets go, I bought the smaller Beorn set and the MEA set but haven't put them together yet. Even though they look really cool, I only plan on buying one copy of the MEA just to get all the characters even though building an epic battle scene would be a ton of fun. The sets seem reasonably priced for a licensed theme, but I was surprised there are only 4 sets this year, possibly because they sort of made 2 DoS sets already last year. Regardless, they are a better alternative to the Castle line that is out, which I'm not interested in at all.