My understanding is that the first expansion fixed many of the launch issues; I played it a ton in between the second and third expansions, and while it wasn’t a AAA game, it was still a very enjoyable sandbox. Watching the IS map evolve over time was great, and eventually the whole thing turned into 'mech Pokemon, which I got sucked into but could be very dry. It was pretty far from MW3’s crafted campaign, but the first expansion did add a number of short and sometimes memorable mission chains all over the map you could run into, giving a bit of that campaign story experience. The second expansion added another campaign you could choose to pick up, but I never did so I can’t comment.
Caligvla