As someone else listening to GGP with zero plans of watching any Gundam, I think it's freeing to outright know I'm never going to watch the main show(s) they cover. xD The shows that are most likely to make me go "huh, maybe?" are the ones they mention in their "what anime have we watched recently" segment at the beginning. (Still haven't picked anything up from that, but it's the right level of detail to make me go "oooh interesting!") But otherwise, like, GGP is the way I've chosen to deal with "what even is the history of the mecha genre" question.