All of that "we're not ready" makes no sense. What, genetic alteration? Forced implantation of reaper tech? It's obvious that Cerberus is going for human dominance. But Reaper tech is really dumb, seeing that's purely tactical and logistical.
We're not ready to take in Reaper enhancements as a species without knowing what they do and are.
We can see in ME3's story that while Shepard and co. are hoping that a weapon will work for them, TIM is eventually stubbornly pursuing a concept that is relatively weak.
Paragon Shepard is more open to understanding the concept, for sure, even as he opposes it. But he won't pursue it at the cost it comes with (see: Cerberus' actions since..ever).
Reaper tech itself isn't dumb. It is just tech, and it is incredibly advanced. If we were against Reaper tech entirely, we'd be against the relays and more, and us using them becomes hypocritical. We can even understand more of the nature of Reaper indoctrination and huskification.
The thing is though, this knowledge came at the cost of immorality. Cerberus did what we would not, because, you know, we don't want to be evil.
But if we were somehow given a break from any Reaper conflict for another 50,000 years, I'm sure that anything we consider to be dangerous-Reaper-tech, will just be seen as the new standard. Cyber upgrades? Sure. Intelligence networking? Sure. Data preservation? Sure. Protection of all? Sure. Because we'd be given more 1000s of years to take it in, instead of, like, 10-20ish.
TIM is pushed more and more into a domain that isn't his, and pays for it.
Reaper tech isn't purely tactical and logistical. Its upgrades actually increase brainpower significantly (I know Cerb troops sound dumb, but they're actually very good fighters for their lack of experience, and only kept lower due to control over them), and its networking could facilitate an Internet of minds. It would revolutionize everything, and if humanity held the keys, it would be dominant, just as the Reapers were for millions of years.
But Rachni/Creeper shock troops? What good do they do? Does Cerberus really think that having some more infantry means anything? Humanity can't compete with the Turians/Salarians/Asari, and won't for a very long time. Even after the war, does Cerberus-analog still think that the other races of the galaxy aren't going to be getting better upgrades? It's nonsensical.
Rachni = understanding of networked minds.. with a queen
Creeper = understanding of networked minds.. with a mastermind
TIM wants to sacrifice his humanity so that he can be the new king of a galaxy. Not 'protector' like Shep in Control, but king - putting humanity on top, and if everyone is networked into his rule, they can't resist his Order.
He wants to Reaperfy everyone, eventually. That's made pretty clear with his dialogue and the side-info. While he may have first seen it as possible to maintain organic prominence, he is eventually driven by all sides into believing fully in Reaper power and supremacy, even if he doesn't believe in the Reapers' goals themselves.
And that's what makes him bad. Shepard, even with Control, doesn't indicate to us that he wants to Reaperfy/huskify everyone + with his rule. He either will 'watch over them' in Control, or do a proper and non-selfish merging with Synthesis. Not the corrupt combination of the two that makes the Reapers so dangerous and evil. TIM's biggest problem is his innate selfishness, even as he poses as a false savior.