There is a slight problem with your idea. With ISE giving out 30 Omega Marks, more people would try the other STFs since they want more Omega Marks/minute. With the current system, the less competent people will only do the ISE until they are at the point where they want a challenge. Do you really what incompetent people doing CSE, KASE, or any of the others and ruining your chance of a successful run? If anything needs to be done, then increase the rewards of the other STFs and not nerf the rewards.