I have never owned a nordica 20 but I have had the pleasure of seeing one and was very impressed. It is a micro traditional sailboat with efficiency and utility as its banners. It reminded me of a Havsfidra in its elegant traditional lines and hull and its spartan yet thought out interior. If I were offered one I would take it in a split second. The owner I know had only two complaits after 2 years of living on it.
1. it took him a while to get use to how it handles in fowl weather.
2. it took him only one time to figure out never sleep on the port sette' with the table down!
I guess it really boils down to how and where you sail, short hops or long hauls. Also, can it handle provisioning for those hauls.
Loving what you sail is important, if it is a proverbial FIT then there should be no reason to change unless the idea of your FIT changes.