Yes, fixing the MCAS software should solve the problem of the 737 MAX. But with all what happened, authorities are extra thorough before allowing the 737 MAX to fly again. Probably all what is needed is a few more months of patience.
On the grand scale of things, the bigger issues with Boeing are how they do business and all the problems with their facturies that have surfaced recently. Beyond getting the 737 MAX to flight status, they have to resolve all the issues and the management problems which lead to them.