I'm always sort of disappointed when St. Patrick's day does little more than green and shamrock designed pets and items. Like St. Patrick did some pretty interesting stuff, banishing snakes from Ireland, making his walking stick turn into a tree, etc. Then there is the leprechauns... oh so much green, despite leprechauns traditionally wearing red. I'd love to see a traditional leprechaun outfit in red in the future. Also since St. Patty's day is basically a love letter to all things Ireland, more fey designs would always be nice (The selkie rats were so awesome)! But I get that doing the stereotypical Irish symbols makes pets and items more recognizable.
...Wait... maybe there are no snake designs because ST. Patrick banished them?... hah! Brilliant.. that's gonna be my head cannon now.
Edit: just noticed we got some snakes and staffs in the 2011 event. Awesome! Still wanna see more of that!