[mindundermatter]

it seems to me that compressors aren't doing the job we want them to, which is to level out the volume level without colouration.

I don't think you're looking at it from the right direction. GB is right; anything added to the chain will also add some 'color'; whether it be from an EQ, compressor, gate, reverb, delay, it doesn't matter. In fact, some people prefer specific compressors or EQ units BECAUSE of the color they add. Meanwhile others cling to specific units because they are (supposedly) 'transparent', i.e. they don't add any color (which is absolute bullshit, there's no such thing). For example, API preamps are typically considered to be fairly transparent because you can have them at extremely high gain settings and still get a crystal clear sound. It's the same with compressors; however when you change amplitude settings for any recorded sound, you inherently alter the EQ as well (because of the way our ears work) and therefore add 'color'. When you add a device (compressor, EQ, etc.) to your chain, in the analog domain, you're adding extra wires, resistors, and all sorts of other electronics which 'color' the sound by messing with the voltage levels. In the digital domain, the same thing happens, only you're adding lots more 1s and 0s to your chain rather than electronic components. So, you're best bet in the long run is to have the best/highest quality signal chain possible from source to microphone to cable to preamp to interface to DAW to monitors (or whatever variation of that you may have) and only add things like EQ, compression, and various effects if they make this chain sound BETTER.