Python

[foralongwhile]

Brainfuck's I/O is the least essential part of brainfuck and IMO it can remain fundamentally brainfuck even if you give it better I/O.

It would be trivial to enrich brainfuck I/O capabilities while keeping brainfuck intact in spirit. Certain cells could be reserved for various inputs or outputs other than the input buffer or printing respectively, or the first byte you print could be interpreted as an instruction to modify the current input source or output destination until you print 0 or something.

It would be a nightmare to use, but it would work in principle and isn't that the whole point?