The thing is, it's not fun. I will explain below.
using the system described, you have the emperor speaking to the top civilian or military minister and setting limits (weed out all officers below 6 loyalty, and all civil servants below 6 integrity). then the automatic systems go about achieving those averages. sort of like setting your tax rate. nice and hands-off, high level, just like you want.
Right now when I play and I decide to weed out all corrupted official I do it this way: I click on a planet and see the governor's face, I see Corruption 10! Great, the mouse moves over Fire button and stops because I notece he is Competence 12 and Loyalty 7. Right... I'm not so sure now. In addition I look at his faction affiliation and I see Warlords faction which is 14%, so he is from an underdog faction and I don't want to weaken them even more because the imperial stability will fall, in addition I plan a grand military campaign soon and the Warlords faction grands me a nice perk then, but only if they reach 25% or more :) So, I sigh heavily and move on to the next planet and then fire someone who is only Corruption 8 but was more disposable.
It's a non trivial decision, taking into account a lot of factors and super cool to make. I don't want to take it away. And it works on an individual level only (or on a limited numer of targets only).
I'm not saying I won't make some bulk fire option, but... it's the last resort that kills most of the fun of the system.