The Westminster model is precisely less frightening because of that. In such a model, regional parties and single-issue parties would have some room to at least get into parliament. This allows for more diversity of opinions, a plethora of options, and a reduction of the powers of the individual parties. It's impossible for a parliamentary government to devolve into absolutism in a country with a strong democratic tradition like the USA.

In fact, I'd argue that a parliamentary government has a greater chance to fall into dysfunction in some cases. Just look at the Israeli Knesset before the war.