My idea is to merge all existing ice ores (in which there are isotopes), isotopes and fuel blocks into the one ice/tope/block type.
Currently, the fuel blocks (and isotopes) are consumed mainly by the upwell service modules rather than the old POSes. There is a 4 different blocks, but you does not have any reason to buy any other than the cheapest one.
It will increase the usability - you do not have to choose one of the 4 existing types of blocks, you will not be confused in 4 types of fuel for capital ships.
This will also reduce the market items list a bit and reduce the spread of prices between the 4 types of ice ore, because only one will remain.
POS still exist and each control tower still requires it’s racial fuel variant. Capital ships also use racial isotopes for jump fuel. As I recall, the original plan for Upwell structures was an new fuel block that required all 4 racial isotopes to make.
The debate is whether having racial variants provides interesting choices or needless complexity. We’ll see what CCP thinks when POS are finally removed from the game - I don’t expect anything to change before then.
That debate already got asked & answered by CCP as needless complexity that had a design idea behind it that failed in the real sandbox.
However removing them now would likely be a non trivial exercise.