What about trying harder? It does not need to be a black or white thing. (either making mem above 0x80000000 available to everything or nothing at all).

For example what about allowing all the executable code sections of ELF files (libs, exes) to be at address 0x80000000 and above (excluding maybe 0xFFFF???? as that could theoretically brake library function tables which are assumed to be offsets instead of pointers if first word in table == 0xFFFF).