The nerf is funny because they did it with the hopes of saying that they nerfed CoH and all was well but every killer immediately saw that they nerfed the one thing that wasn't the issue with it. Nice try behavior.
Really? That seems weird, since 75% of 50% is 150%. I guess it depends on what value they will actually add to the 50% healing speed of the self healing speed. I hope it would be 50%, that would be fitting to the idea that you can heal yourself at 75% the normal healing speed. But if it's just a 75% healing speed boost to the 50% self heal speed, than it would be the math used by you two. Which would really be a very minor nerf.
Your logic is wrong, 75% of 50% is not 150% but 37.5% (0.75 x 0.5 = 0.375). A percentage of a percentage is a multiplication, not a division.