Yes, Afghanistan is a much better team than Zimbabwe. Even they are so good that they could beat Zimbabwe, West Indies, Bangladesh, Sri Lanka and Pakistan very easily. They may also give a tough time to the big three teams, but sadly I don't see them playing any international series lately. We are witnessing one-sided matches where West Indies and Zimbabwe are losing matches without making any efforts, and this decreases the viewers' interest when they already know who is going to win.
People will be more interested in watching matches between Afghanistan and Ireland compared to matches between New Zealand vs Zimbabwe or Australia vs West Indies.
Afghanistan deserves a few matches against teams like Australia and New Zealand. But I believe that some of the SENA boards want to expel Afghanistan from international cricket and that complicates things. Even associate nations such as Scotland, Netherlands and Nepal are now performing better than Zimbabwe. And that too with 1/50th of the funding that Zimbabwe receive. But the ICC remains blind to this and they continue to prop up Zimbabwe by pumping tens of millions of USD into that country every year.
There should be a clear and predictable paths to ODI, T20I and Test status and any teams with those status should get a chance to play with every other team in regular basis. This limited cricketing structure has always hampered the growth of cricket as a global sports. When ICC became more relaxed and set a path for ODI status and as T20 became the new favorite sports that anyone can play and get a International status, many new teams has emerged. Afghanistan is a success story but there are many more potential teams like Uganda and Italy that could in future come to the central stage if ICC promoted all assosiates.