It's great to see some DLC, and I don't mind paying for it - that's not the issue, anyone who thinks it should be free probably doesn't realize how much time and money goes into making maps and expansions for games now as they're far more complex than from before.
What I don't like about it is the exclusivity deal. Sure it's business and it happens, but if you're Bethesda you end up alienating part of the community. I happen to prefer steam as I think it is a superior service that is not as intrusive as Live (See GTA 4 for an example). Since there are no other alternatives at the moment, then I'm not going to buy it, its really that simple. I'll just wait for it to hit retail.