The public trials early in his administration largely performed glorified public shaming. Things went wrong when Sankara had to delegate oversight, and found, to his frustration, that not everyone was an idealist with a one-track mind like he was.
The militia were hilariously inept, and not much more than glorified national boy scouts - not sure if one wishes to count that as a positive or a negative. The militia were meant as a counterbalance to the professional army (which would eventually end up couping Sankara, suggesting that the idea was not unsound).
"Tribal customs" are generally a euphemism for patriarchal control by local elites.
No defense for his arrests of trade unionists.
Nor any defense for, unlisted but worth mentioning, his rejection of national elections as a means of expressing democracy, his dissolution of political organizations (including his own - Sankara's lack of political instinct repeatedly came back to bite him), or his glorified corvees towards symbolic 'anti-imperialist' projects that did not improve the living standards or economy of the nation.