If you want a putter to stick and you already like the Warden and Shield, then pick one up in Classic Soft/BT Soft. I putt Crowns in the circle and typically use BT Medium plastic; if I I'm playing a course with some stupid fast greens, then I'll put a BT Soft Crown in the bag too. And while the plastic does get gouges fairy easily and show some wear, it really doesn't seem to change flight characteristics nearly as quickly as you'd think. Especially if you're just using it to putt and not to drive with.
Alternatively, if you really want a putter that is soft with maximum durability then you're best bet is to check out a putter in Neutron Soft plastic from MVP/Axiom. I have abused my Neutron Soft Envy and yet it still looks and throws like new. I typically use it for C2 putts, stable upshots, and a little bit of driving duties. It also gets C1 putting duty on days when my Crown is misbehaving and in timeout.