I can see only benefics when I think in procedural parts, for that reason I want to open a discussion.
For me is the only logic way that KSP has to improve the game limits, time to build and reduced count parts that it will traslate to better performance in frames and time to load..
First some examples of what I am going with this.
I guess many of you already know the mods (Procedural fairings, Procedural Wings, Stretchy Tanks and Modular Fuel System).
Now lets start to think, how many parts we need to have all the possible fuel tanks that we maybe need? Now, you need to multiply that amount for the different kinds of fuels.
If we have dimmensions from 1-25 to 5 and then 1 orange tank "large" to the X200-8 Tank "large" you have 16 parts without count different fuels and smaller tanks like those in RCS.
Of course you can have an small tank and then put one over the other until you reach the amount that you want.. But how much performance and loading time are you wasting?
Also wings, how many parts we need to make almost any shape? Even with B9 I cant make the shapes that I want sometimes. "well this guy can said something about it; but this wing structure it does not allow a future improve in the aerodinamic system."
Procedural wings fix all that with just 2 parts. And you can improve the aerodynamic system in the future and it will be easier to adapt.
I guess had a lot of mods just to fill the posibilities of part that we need is not healthy. This will give us hundreds of parts in the whole game.. And if we want to search one from all that it will be very difficult.
Maybe someone can say that is more real if we had certains products between we choose. But is not the case. Becouse factories commonly had many sizes of each product they produce. Also in the space industry almost all is made just for the occasion.
So what I am saying?
I guess KSP must incorporate these mods to the vainilla with some changes.
For example, stretchy tanks it does not use standard sizes. The problem with that is you are loosing the scale parameters with other parts.
A better way to do it it will be with 3 different shapes of tanks. Cilindrical, Spherical and half spherical-cone shape.
In cilindrical you had the width that you can alternate between (0,65 - 1.25 - 2,5 - 3.5 - 5) and large (from 2 times a orange tank to a half X200-8 Tank).
Once you had the tank, you fill it with the fuel of your choice. In this way the cost of the fuel it will be independient from the tank. Also you can choose Liquil fuel, or LF and oxidizer, Or RCS or other kinds of fuels that the game can incorporate into the future.
In carrer mode maybe we can have the option to choose different materials, in this case it will be notice by different textures.
The same for girder segments, or adapters, batteries, anteenas, ladders, parachutes, gears, docking ports, control surface, winglets, solar cells, reaction wheels, decouplers, etc.
In the case of engines maybe it can be implemented in advance mode something like Scoundrel´s suggestion, I dont know..
But just with that, we reduce the count parts from more of hundreds to 30.
The Fairing mod is also a perfect example. That mod is great, maybe we can have a dynamic base plate too and then we reduce even more, from 8 parts (fairing mod) to 4 parts (all posible fairings).
And I guess if the KSP team decide in some moment make a change to all procedural, I guess they can ask help to the comunity and we will be willing to help.
They just need to dictate the norms that they want for each part.
About the tech tree, we can upgrade different sizes parts.
What are you thoghts? Some cons?
Some examples of the part selection, are explained here: