My concerns here are that there's too much attention being devoted to aesthetics and not enough to functionality. Doepfer modules are really excellent...but they're often pointlessly big, an issue which Dieter has been working on fixing with the new, smaller modules.
Take the A-141-2, for example. ONE single CVable ADSR in 14 hp, costs $190. But then, look at the Livestock Leap...also one loopable and CVable ADSR, but which ALSO offers offset and inversion. So, right there, you'd wind up eliminating the A-141-2...AND the A-183-2, AND half of the A-133. And it costs $5 less.
The real power in Eurorack and the plethora of modules that exist for it is in being able to mix and match things. Sure, it looks cobbled-together that way. But you can effectively jam MORE functionality into the same space, and in quite a few examples, you can save money while doing that. I wouldn't suggest making the various modules smaller in this size of build...but I do suggest that you can wind up with a far more potent system by NOT locking yourself into a certain "look", and building more along the lines of maximum capability. In the end, nobody cares what your system looks like, but they sure as hell will know that building for more function will equal far more musical flexibility...and THAT is what an audience looks for.
Oh, yeah...explaining linear and exponential...with LINEAR VCAs, envelopes, etc, you're imposing a change on a signal that follows voltage scaling. If you need to change the voltage scaling so that everything still tracks properly as far as CV values, you use those. It's also why linear VCAs are almost always DC-coupled, because they fit better at modifying CVs, modulation, etc. EXPONENTIAL VCAs, envelopes, etc, though are AC-coupled, as exponential relationships are what governs how we perceive "apparent loudness". Remember: the decibel scale is a LOGARITHMIC curve of values, and NOT linear. Note, though, that you can get away with only linear VCAs in a build as long as you have exponential EGs to make them conform to the exponential loudness curve. See here for a more in-depth explanation of this: https://en.wikipedia.org/wiki/Loudness