Even in a very crowded field, Marwyn, the Nurturer still stands out as one of the best Elf Commanders around
(And, conversely, if you're the one with the Bronze Sable, you should not trade.) You should always think about what's in your hand and how the game is going to play out when considering a potential trade
This is an Angel (so will have some interest), but will also be another $1.50-$2 card in the end
Not only do you turn your non-creature artifacts into 4/4 creatures, but you also give them flying, providing them with evasion
Its overall flexibility and offering no cards to your opponent I think will have it see much more play than Jar
Right now that target is mostly Dig Through Time