I realised that Spring Dawn Gawain and Spring Dawn Kenshin are both gold tier in nyan and if you check at yorozu exchange, both summoner’s scroll at priced at 85 Yorozu Limited Ticket but normal Gawain and Kenshin is platinum tier and is priced at 170 Yorozu Limited ticket, does anyone know why?

Does this imply that Spring Dawn Gawain and Kenshin are weaker?

Yes. All gold partners so far are really weak (idk about these new ones). You shouldn't care about them; bec they usually appear in Nyan, only the plantinum that change.