Haha, I bought the complete Mii Plaza package back in the day, and Flower Town is my second favorite of the four games. I have to say that it's actually Warrior's Way that keeps me coming back. When it comes to these games, I find that it's the more simple games that suit the StreetPass features the best.
But I really hope that Nintendo continues to implement StreetPass in their future hardware. That and Miiverse are probably my favorite hardware features so far this generation. I'm always finding excuses to take my 3DS with me wherever I go, even If I have no intention of playing it. Seeing that green light always puts a smile on my face. ^_^
Anyways, Grezzo is really an interesting developer team. After creating an amazing remake for arguably the greatest game of all (Ocarina of) Time, they go on to create the greatest (RadishHead) game of 2013. Legendary for sure!