There's nothing to prevent you as an individual flying on QNH rather than QFE.
True bit it can get a bit more complex when flying through a MATZ and they give you QFE to fly on. Granted to an experienced pilot this is no big deal but I agree with the original poster than QNH only operation for all would be simpler but there again the QFE/QNH debate is as old as aviation almost so I'm not holding my breath. Trouble is in UK we don't really have any "high" elevation airfields. Try setting the QFE in Nairobi or Mexico City....