MCAS I think was a good idea but poorly implemented.
First - it should be disabled and not activate if there's an airspeed disagree or any detected issue with AOA indicators. That's a simple fix. Frankly this system activating during such a circumstance is just exacerbating an already existing emergency.
Second - it should not be allowed to get to full nose down trim below a specific altitude - Boeing can decide what that altitude is but I'd say 10000 feet and certainly not 6000.
The purpose of MCAS is to help with stall recovery with high power settings. Tests could be performed to determine what the max nose down trim should be with full power, but I'm certain it's not FULL nose down trim. Limit it.
I think that this can be fixed and the fleet safely returned to service. I'm sure smarter people than me at Boeing have already considered what I'm proposing.