What is the most important theme or problem that Latin American philosophers are dealing with?

Probably marxism as liberation theology, aka dogma, re developmental concerns shared especially in Asia and Africa societies.

Olavo de Carvalho has a cogent critique of what he identifies as a cartesian turn to what he terms "cognitive parallax," the psychologism of erroneously imposing one's own issues onto society as a whole.

Carvalho then analyzes this displacement or projection specifically as applied in the liberation theology, becoming an illogical first order set of "class" vs "class."  The individual tyrant-philosopher treats opponents of his or her system as enemies, rather than a) evaluating reality and b) processes that may bring helpful change to the whole.  This processing is not per some rigid, imposed "cognitive parallax"-style hypothesis, but problem-oriented re gathering relevant data and making changes thereby.

Good luck finding anyone here who knows or cares. Besides that, "Latin America " covers everywhere from Mexico to Tierra Del Fuego and the Carribean nations, and their problems and concerns are so diverse that you do a disservice by suggesting there is a single most important theme or problem that applies to all of them.