I don't see much difference, except for the existence of variable length instructions making decode harder. Having fully hardwired decoder from macrocode to mic

I don't see much difference, except for the existence of variable length instructions making decode harder. Having fully hardwired decoder from macrocode to microinstruction was pretty normal for early microcoded architectures, because a simplest such decoder is to latch the opcode as part of ROM address with ROM output being a wide microinstruction. If you ensure the indexes are actually multiple microinstructions away from each other (for example, shift opcode to upper part of uOP program counter) you can easily map multiple uOPs when necessary without branching into more complex microcode.