Balance is a lot more fine-tuned then to allow something like reducing all damage by half. I can't begin to describe how many problems that would cause, certain ships/builds would be un-viable, others would be completely unkillable by anything short of an entire fleet focus firing.
Every single space related number and mechanic would have to be re-tuned to compensate. They might as well just throw 33% of the game out and start fresh. Your basically asking for an entirely new game.
Have you looked at any of the numbers you have proposed and actually done some math? Reduce by half, reduce by half, reduce by half, 4x this, 2x that. Its madness!
Tanky ships would be completely invincible, The only ships that could possible do damage are escorts and science vessels with incredibly overpowered AUXx9999 science abilities. No one would ever die in PvP, Even if the entire team focused one person, Because the lowered damage, shield regen, and 4x as powerful aux/shield powers.
STFs and Bosses/Events would take HOURS, travelling between objectives would take way too long for anyone to keep interest in the game.
Absolutely no offense to you personally, but what do you actually hope to accomplish with this outlandish numbers? How much STO have you played? How much theory crafting have you participated in? I don't personally see a reason for any of this, other then to otherwise ruin a perfectly good game. (Not to imply there aren't many improvements that could be made, or balance issues, but certainly nothing good would come of this)