I'm currently not able to go through all the replies here, so I apologies if I'm echoing someone who said it first.
I agree that hasten is to common, worse yet is how hard you have to stretch many builds to even come close to justifying dropping it, however these solutions are problematic. There is a reason why fitness was made inherent. I can get behind your second option, basically making hasten less powerful but double stackable to achieve the same effect as now while allow for lower investment versions for other build, but your current 3rd option suffers from several issues.
First is time to implement, while the changes you suggest are minor, the implementation of them would be time consuming, while i don't have a firm knowledge of the game's underlying structure I suspect that many values are not simply available in a database you could run a script on, thus in at least some, if not most cases, these small tweaks to enemy health and player ability recharge rates would need to be done by hand, given the number of powers and enemy values in the game, this would be a tedious task at best, and a monumental one at worst. This isn't including the time spent ironing out mistakes and bugs this could implement.
Second, while I appreciate your mathematical breakdown of your changes it doesn't cover a wide list of cases where this change would be very disruptive. Your focus on TTK/TTD is unfortunately to reductive. Firstly there is how regeneration works in relation to health, regeneration would need to be tweaked as well in this change because a 9% increase in health is also a 9% increase in regeneration rate as regen is a % of max per second. This becomes especially bad at lvl 35+ as your proposed 30% would drastically improve the durability of many AVs and make many builds unable to solo them when previously they could, even without hasten. This is so drastic a shift that even EBs may become to hard to kill for lower damage classes. This is a problem as a core design tennate of CoH it to make it solo friendly.
Another place this health boost becomes an issue is in the TTK itself. While taking your targets health and dividing it by your DPS to them is a quick and dirty method, a more accurate method is to take their health, divide it by the number of attacks you have to use, then add up those attacks cast and recharge times. (this is omitting the additional factor of how much they will regen over the course of the fight) Damage comes in waves, and if previously 5 attacks would kill a mob but only just, a 9% health increase will make it 6 attacks, that is not a 9% increase in time, its a 20% increase.
So lets try a hypothetical power with a 1 second cast time and a 5 second recharge time, we will stay at say level 4ish and this is your only attack because admittedly more attacks will smooth this out. The attack does 10 damage and your enemy had 50 health.
Normally this would take 5 casts, so ( 1 + 5 + 1 + 5 + 1 + 5 + 1 = 19 second TTK )
Under your changes the values become (roughly since i dont have the recharge formula at hand) 4.3 recharge and health of 54.5 (tenths place HP is tracked)
This results in 6 casts so ( 1 + 4.3 + 1 + 4.3 + 1 + 4.3 + 1 + 4.3 + 1 + 4.3 + 1 = 27.5 second TTK )
This is a 31% increase in actual TTK, at low levels this could easily cost a blaster or other squishy AT their life.
Obviously im cherry picking a situation here, but the point is to show how changes to global values like this can have huge ramifications, this is why it has to be approached very carefully since any cure the the woes i just outlined while keeping your proposed changes will require exponentially more work and effort in rebalancing the game.