RTF is extremely easy to parse if you assume it isn't using an ancient code page. This is a pretty safe assumption since almost no modern software even supports all the code pages in the RTF standard. Word is far more likely store Arabic in default Windows-1252 with \u_____-specified code points than to use code page 708 or something.

Is it as easy as Markdown? No. But it should take about an afternoon for a halfway competent programmer to make an rtf2txt utility from scratch that correctly handles > 90% of the RTF files you're likely to encounter in practice.