The Kett as Enemy are Very Disappointing, same as Reapers

Still not even that. Mealting down organic to be made to something it can use is not the same as turn bob the argarian  to steve the kett.
The reapers were turning organic to tool and machine it can control.
The kett are turn people into more of their race. they not tool but new people of there empire. Not the tool to be used and thrown away like the reapers do. And even when reaper do tur organics into a reaper it's still just to control and preseve organics. they don't need to do it.
The kett are just making people in kett because they think it's beter for them to be kett.

That hands down the borg.

the Jardaan though are nothing like the prothean. Grooming a race is not the same as creating a race. Making a race is far more daunting and complicating and give big changes to the idealiology of that race when they find out they are made.
But grooming a race. the asari are not the only ones and were shown doing that from ME1. You're just improving what there. 

think of it this way. What do you think would happen with humanity if they found out they were tampered  and observed by aliens in the past at the dawn of our civilization well after we came from caves, now compared that to how humanity would react if they were made by an alien race?

it's that big of a difference and it's something new to ME.