I agree with the sentiment OP but not your analysis.
TIER 1: Longshot is the only talent. Covert Ops is a trap. The slow is increase is big, but the real reason it seems effective is becuase it forces you to be closer, so you get more autos in before the hero could run away. Its totally overkill if you step closer. Advanced cloaking was just fine before they delayed the movement speed increase, revert that and get rid of the mana regen. When it dropped from 4 to 2 and they lowered the snipe cd you dont spend enough time in stealth to make that regen impactful.
TEIR 2: my defualt is rapid projection for small maps, larger maps covert mission. Holo stability is garbage for a number of reasons, 2x damage on decoys means increased duration is pointless, how dumb the ai is, between sometimes not attacking anything and others just standing still trying to auto someone for no damage, it fools no one. Id like to see this talent remove the bonus damage the decoy takes so its harder to get rid off, allowing to maybe delay a channel a bit longer but also not being a dead give away when it takes damage.
TEIR 3 you skipped. I assume like me, you find a niche for each of these talents.
TIER 4 TT is definitely one of the worst ults in the game. I think what needs to change is the all or nothing for 100 CD. Give it the Rain of Vengance treatment and allow it to store 3 charges of 1 shot at 35second CD per charge. Could even tone the damage down a tad to compensate for the flexibility.
TIER 5 Ionic field needs an in stealth effect. Whether its the same armor, or maybe 2% health regen per second…something. as is it will never compete with the other talents.
TEIR 6 technically all the talents are good, i feel like if you fix holo stability or the ai in general lethal decoy would be more attractive.
TIER 7 Apollo suit should increase the number of decoys you create from 1 to 2, including ghost protocol. Its a lvl 20 talent for goodness sake, lets make it sexy yeah? Fast Reload with my previous change, restores all charges at once. Delete rewind, totally agree its hamstrung her for a long time. If you must have 4 talents, i guess increase the range of her basic attacks and abilities by 2.
At this point in the game, she needs to stay what she is. We can get tosh or a no name to be a real ghost hero… maybe.