I think we should do away with download clients, as much as I love Steam. Online stores should sell their current games DRM-free as GOG does with old games, and each publisher should have their own online store. DRM doesn't stop pirates and I believe that today it is not present for that purpose, but as a way of making some people pay more.
No way. Steam came about and became successful because being a PC gamer used to mean installing a game and then manually installing a bunch of patches with very little user support and often (at the time) these patches not being easy to find. SiN is a classic example of that, where to get the game mostly stable you had to install the game, then patch 1.3, then the expansion, then retropatch to 1.2 and it was still buggy. There's no way in hell I'm going back to that.
Also I live in New Zealand, and while many games get here relatively close to release - the Steam library and store is just so much more convenient. Even some online stores in NZ I'll go to order a game only to find it out of stock and therefore like a week or more away.
As to the issue at hand, similar to my other pre-Steam games there have been games where the Steam version and the non-Steam versions are incompatible. For example if I had ME1 on disk, I wouldn't have been able to import my data to ME2 - and the same goes with DLC. This seems to me to be the big problem, and Valve would get in a bunch more trouble if people could buy Crysis 2 on their platform and suddenly find that they can't get the DLC. I wonder how recently EA announced the exclusive deal - I suspect it was around the time that Steam pulled the game. There is a certain amount of big fish bullying here by Steam, but at the same time it's perfectly in the guise of trying not to mislead their customers.