You can do this with scripting.*Make it possible to make units with multiple damageable parts (the unit can, for example, become unable to walk if its legs are destroyed).
Ditto.*Make it possible to make units wich efficiency can be linked to its health (I mean, if the unit is damaged it will not perform so well as if it was perfect).
Sounds like pointless micromanagement, tbh. But you could probably implement something that would let users do this via the new GUI stuff.*Make it possible to give builders building priortys so, if you have stall, the builders with lower priorty will have their share of energy and metal reduced until the higher priorty builders can build at max speed again.
This is quite possible, but ... rather difficult, due to the way Spring works. I have looked at this enough to know that actually achieving this will require re-writing the core loop basically from scratch. Not impossible, just very time-consuming. And I do not have the time right now. The "how it is gathered" part is a lot more complex territory, frankly, and I could spend pages talking about it, but I won't, because this is all just theoretical anyhow unless somebody has the free time and skill to rewrite the core loop.*Make it possible to add/remove/edit/ resources (What I mean is being able to add another resource beside metal and energy and chose how he is gathered).
This would be possible if Features were actually Units and could make use of scripts. Which I've already said in this section of the website. In detail. Twice.*Make it possible to have diferent reclaiming animations depending of what is being reclaimed.
Do you not pay any attention to what is going on in development at all?*Make it possible to add buttons to the orders window and chose what they do (With also the ability of only having certain buttons with certain units).

I guess what I'm trying to say is that:
1. You really need to learn how to script. Sit down with NanoBlobs and start learning, so that you will quit asking for features which are already available.
2. It's ok to ask for things around here, but most of what you're asking for is MTR, or are bad ideas because you don't understand the technical ramifications of what you're asking for. That's why you're not getting the response you want- either what you're asking for is already possible, or it's in the category of, "yeah, maybe when it's stable again" for the main developers, I suspect.