Problem is Dresan, your suggestions would change nothing, The number of people that pick infiltrator or scout would not go up, The ones taking miscreant and stalker would not go down, the types of subs taking those classes would not change and the other (stated by Brokkr) Reason for the changes is to move Infiltrator a tiny bit closer to assassin and scout to actually be a scout.
Infiltrator or scout getting master poison and scan? Who cares? Totally useless change and I believe you know that.
Now, myself, I do not really think Brokkr's proposed changes will increase the number of mages that take scout and infiltrator. My experience is, depending on the mage type You want either HIGH utility, which stalker and miscreant still would fill, Or you want Master levels of combat brute-ness, which Infiltrator and scout still would not fill.
But it might change the overall demographic some while bringing things more in line with whatever vision he has for those classes.