I prefer him not to be seen or existing at all. It's way cooler when the Autobots defeat this enemy by themselves, than having someone like Primus on their side. Although I don't like having such religious stuff in my favourite show. The only interesting religion (storywise) to me is the northern mythology about gods like Thor or their greek counterparts and their stories about Hercules, etc. But I don't want analogy to christian religion in Transformers. So I'm pretty fine with Primus not showing up. I'm aware that in some continuities he exists and that's more than I need to know. I'm glad he never showed up in any stories that I encountered.