Trump's move is, I suspect, destined to divert attention from other issues that displease him. That he is throwing fuel into a fire, as
@Dennisch wrote, and that such a move might cause more death and pain in and around Israel, isn't important.
I don't care much about Trump or indeed if the American political system is capable of dealing with the "stress test" that is his presidency. America's problem, of their own creation, therefore theirs to solve. But it annoys me that this move is perfect for extremists from all sides. And it annoys me to see Turkey drifting further and further away from its alliances with the western democracies. That summit about Syria between Putin, Erdogan and Rouhani is probably only a sign of what's happening behind curtains in international diplomacy. But only clever diplomacy will stop this from growing into something that will recreate the "us" and the "them" that existed until the fall of the Soviet Union.
International diplomacy is facing great challenges now. Turkey and Iran concerting their agendas in the Middle East is something completely new. And to make maters even more complex, one is a NATO member and the other is constantly being menaced by the USA. Regarding Europe, Iran is less seen as a foe, but diplomatic relations with Turkey are at an all time low due to the loss of democracy this latest version of Erdogan means.
Amidst all this (and I'm not even mentioning Korea and China, another chessboard entirely) Trump announces the USA accepts Jerusalem as the capital of Israel. Great move.