I think African-American is impracticable because we don't often know where someone lives, and their lineages. President Obama is African-Irish-American. Calling him African-American denies half his lineage.
I live in Montana, which is one the Canadian border. If I see a black person, I shouldn't assume he or she is American. Years ago, I met a black guy in Montana from France. We could label him African-French, but what if he had no French lineage? What if he had a half-brother who's mother was African and father was French? African-French would mean two different things in this regard.
On a more personal note, my family was split apart because of ethnic identity. Half my family is Irish, and half my family is Hungarian. My Hungarian grandfather tried to convince his grandchildren that we were mostly Hungarian, and this completely outraged my Irish relatives. Their strong, ethnic identity caused a riff in my family that never healed. This has caused me to have a strong distaste for ethnic identity, though I completely understand why oppressed, ethnic minorities feel strongly for ethnic identity.
I wonder what would happen to the Israel/Palestine conflict if they no longer identified as Jews and Palestinians. If they chose to only identity as humans, or as living beings, would they treat each other more humanely? I think they might.