The reason people put 20 points into marksmanship instead of survival is because you can really add the DPS in MM (especially with Mortal Shots, which requires the last 5 points) whereas in SV you get ~ +3-6% damage to SOME targets, some of which can be made up for with gear (and hit % is cheaper than crit %). In raid, your primary job is to deal damage. That's why you spend the points to get the (at 20% crit after LS) to get 11% increased damage on all targets, instead of 3% on all and an additional ~3.45% on some other targets.
As to CC, in a raid there are likely to be other classes with more readily-accessible renewable CC (i.e. if trap breaks you're screwed) which are specific to the raid. You have the luxury of bringing along 2 priests to kara, for example, while still leaving the door open for a lot of other members. Whereas in a 5-man run, you usually have 3 DPS classes (and tank and healer are likely not to be doing any CC, since they have no backup, whereas priests/druids can CC and still heal well in raids), so hunter's traps are much more needed. That's why in 5-mans you may want to go with an MM/SV or SV/MM build, although my hunter never had problems trapping as a 41/20.
Those 20 points are also the reason 41/20/0 is the top DPS build and why 5/20/36 is the second-best. The heaviest DPS talents are deep in BM and the heaviest raid talents are deep in SV. As to marksmanship, the earlier talents scale better with gear than the later ones, and also provide a lot of extra damage. Thus, rather than pick up the good DPS at early marks and okay DPS at late marks, then pick up the very shallow DPS of early BM or SV, the raid builds seek to get the great DPS of deep BM or SV, and the good DPS of early MM.