I don't think there's more risk of "algos gone wild" than there is of manipulation and malevolence, as there has been forever.
Software bugs combined with human error are a source of danger though, such as in the infamous Japanese trading disaster (someone transposed the size-- 1-- and price-- ~600000 yen-- on a short-sell of an IPO, effectively giving away more shares than existed). The fail was not so much that the clerk put in a bad order, but that the exchange software wouldn't let the firm cancel it, leaving them to eat $225m in losses.
Software bugs combined with human error are a source of danger though, such as in the infamous Japanese trading disaster (someone transposed the size-- 1-- and price-- ~600000 yen-- on a short-sell of an IPO, effectively giving away more shares than existed). The fail was not so much that the clerk put in a bad order, but that the exchange software wouldn't let the firm cancel it, leaving them to eat $225m in losses.