You hit the nail on the head.
Not getting mapmaking tools wouldn't be so bad if they would make maps that were even halfway as decent as some of the community made maps.
Hell radiant (the program used for mapping in CoD) has so many things built into it that the developers don't use in ANY map. One quick example would be doors that open and close.
All it takes to have a door that can be opened/closed is 1 extra brush with a trigger texture, and a few lines of code. (literally less than 30 seconds to make an interactive door)
They could even take it one step further and make doors that can be opened/closed, and will also be destroyed after taking x amount of damage.
They could make walls that crumble/get destroyed after taking x amount of damage.
Those are just two quick examples of things in community made maps that are not in developer made maps. The tools to do everything already exist within radiant, it would take virtually ZERO effort at all for them to make the maps alot more interactive.
The worst part is the developer made maps are all two dimensional. There are no secret tunnels or sewer pipes or crawl spaces, and no verticality to any of their maps at all. Take a look at burg on CoD4, a fantastic community made map of a castle and surrounding farmland. The map is riddled with tunnels and passages, ivy covered walls you can climb, even a well you can drop down into an underground tunnel.... It's a map that is 50 times better than ANY developer made map (from ANY CoD title) and it's just ONE example.
As far as them controlling the game by forcing us to use hacknet, they are doing nothing but hurting their own profits. If MW2 and MW3 both had all the same server/PC features and support that CoD4 had, the CoD franchise would be a LOT bigger than it is today. They would've sold MORE copies of MW3, and the outlook on these forums would be more positive than negative.
I guess the profits they get from selling hacks must make up for what they lose by screwing over the majority of the PC community.