Note: I moved this out of the Support Category and into the GT6 Category, because this isn’t really a “Problem” as is more of a Suggestion Type of thing. I would recommend you to post some notification whenever you edit this thing. 
Yeah a Piston for RU to KU conversion is planned.
The Overclocking Mechanics need to improved for certain Types of Machines indeed.
Multiblocks are “just stupid casing” for the reason that its simpler to build them that way. The delicate “Turbine Blades” are supposed to be part of the Controller Block of the thing. Essentially every “exotic” Part of a Multiblock, that wont be usable for any other Multiblocks, should be contained in the Controller instead of the Structure.
This is more of a Game Design thing than Realism in this case ofcourse.
And there is indeed more Multiblocks planned.
Reminds me that I should definitely fix the 3x3 Front Texture of Turbines to actually be rendered 3x3 instead of 1x1.
Nuclear Fission is indeed planned for GT6, same for Nuclear Fusion and an RTG (similar to IC2 but with more realistic Fuel Pellets, though radioactive decay would be very accelerated in a lot of cases).