Maybe its a bit late to talk about it in GT6, +much of this theme was discussed in a post about it last month, but ill share my little opinion how i would organize it if i ever had my own mod(i like to dream 
).
Personally i really liked Gregorius idea about how different materials have various uses and stats, but i also a big fan of vertical progression. While i was on vacation without wifi, i continue to think about all of this and how to combine it… And i introduce maybe the worst ever gamedev solution, mostly because it only makes things worse…
So, we all know about machine hulls, and we all need “imagination” to use them, heh. So, why cant we give them proper use? My idea is mostly about it. Ill try to explain it in a form of some mental discussion.
Machine hulls has many tiers, but what if we had several machine hulls of the same tier? (Imagine we have them) . Now, they give different modifiers to machines, like powerefficiency or speed. What else gives them? Ye, parts! Instead of crafting machine, u place machine hull and start assembling it(i took this from SpaceStation13 game, maybe someone here knows it). Firstly, u place main casing, that defines machine type. Casing doesnt have levels and is needed only to make proper machine. Then u decide, will machine make needed energy type(ku, ru etc) by itself at cost of power efficiency(Way 1) or accept it at cost of factory’s simpleness(Way 2).
Way 1: u have several ways to power, like steam and eu(or convert ru to ku brrrrr-) . Ill explain on steam energy. We make steam piston(as example, gtnh april fools moment) using black bronze(85% power efficiency and 105% speed for example) and place it into machine(imagine we are making some sort of crusher). Its only possible to add parts of ±1 tier(so u can use ULV components in brass machine hull, but cant use steam components in tungsten carbide hull)(For example, machine hull for our crusher will be made of steel, 80% power efficiency and 125% speed). Also u add other components like crushing discs made of GDA(my pack material, dont mind i use it here) with 95% speed and 90% power efficiency. To make auto input/output of items/fluids/energy we have to put conveyors/pumps/coils to corresponding slot in machine hull, u will make auto output with ULV conveyor of sterling argentum with 4 items/sec and 105% power efficiency. (For simplicity your crusher will only use this components). And… You have a crusher with two power inputs(ULV and steam) and one auto-output. Lets calculate its stats. For EU: floor(floor(8eu/t - 8eu/t*0,05)/4(because its only a out/in module). Ok, now for steam. Because black bronze is ULV material (in my mental discussion), and hull is LV(steel) , total power efficiency will be multiplied by 0,9(because of extra tier of hull) + speed will be multiplied by 1,1. Now lets count: (1-(0,15+0,1))0,90,8=0,54 only… Bad power efficiency… What about speed? (1-(0,05-0,05)1,251,1=1,375…
Way 2: huh, i described mostly all things in way 1, major differency is that it wont have piston, but a piston extender(i name this way a thing for applieing ku to machine).
All parts in machine will have durability and stats about it(like speed of losing it) and… Function like HTM rods for rbmk. So this will lead to a real maintrance mechanic and stuff about it, and speeding up machines with component functions.
Also i thought about enchanting parts(or having curses) to have better stats… But this is maybe in other topic.
Sorry for all this mess + for my bad english, this text got so unorganised…