The major change is the political movement behind it, I guess
Indeed, it is all about having an open ISA, which did not exist before in this way. The other big selling point is the modula concept of the ISA. RV32I is so simple that everybody with average HDL skills can design a CPU executing it. And you can just use the out-of-the-box GCC to compile code for it
Just on the debugger side, risc-v has divergence again.
RISC-V debug spec is also quite incrompensible to read and there is no good reference debug server implemtation - it is just a patched OpenOCD.