From a programming perspective, ControlLogix(CLX) and CompactLogix(CPX) can be treated the same. Offhand I can't think of an instruction supported by one and not the other, but the power of the actual hardware is significantly different.

I'll wager the reason you're using indirect addressing is for recipe management. For CLX/CPX you would create an array of structures (UDT) and index through that to achieve the same effect.

One significant difference between CLX/CPX and MicroLogix(MLX) is the ability to set up produce/consume tags (implicit messaging). These simply don't exist in MLX and have to be managed with explicit MSG instructions. This has a big effect on devices like VFD that fault if they lose comms with the PLC. (there's even a technote recommending against using VFD with MLX because of this increased complexity).

Also PID options are better with CPX/CLX, offering dependent and independent forms of the equation, as well as PIDE with autotuning and PlantPAx faceplates.

In general, the MLX is a simpler device. It can still control a VFD, the programmer just has to work harder.