Rightly or wrongly, Bannon helped propel Trump to power with a populist rhetoric based on Far Right politics. Bannon may have had limited impact on US foreign policy under Trump but his presence as a senior strategic advisor to Trump tarnishes the integrity of the US government. See ‘Opinion – Are there white nationalists in the White House? | PolitiFact’.
However, even without Bannon, I would be cautious about a major change in US foreign policy under Trump or possibly Pence.