I'm a fan of the shield design. The Memorial always seemed really boring - very few countries are lazy enough to just put head-on famous buildings on their coins, and any building looks boring from the front. When I was younger always wondered why the Most Important Country In The World didn't have more exciting coins. I didn't know what exactly was out there until I started buying more foreign coins, and now I can safely say that almost anything more than wreaths or words is more interesting than the Lincoln Memorial. Monticello, a generic bald eagle, and the Great Seal are also pretty boring. (I like intricate national crests, but the Great Seal is just too weird. It looks better on the dollar bill.) But I really like the
Roosevelt dime, and the Eisenhower/Susan B. Anthony design is just fantastic. What a shame that it never became popular - the eagle on the moon is so weird that it's awesome. Compared to the rest of American coins, it's a great standout. (Even Susan B.'s portrait is pretty well-done, I've never known why people hated it.)
I think that re-using classic designs would be honestly uninspired. It's like giving up - "oh, the past was better, let's just forget about what's happened since then". And aesthetics change - we now live in a modern age of simple but striking designs, which is why I think the Shield Cent is a great step forward.
Now I can opine about other American modern coins. You shouldn't have given me this chance.
Jefferson's unconventional portrait - I really like it. Profiles are definitely dated, so it's great to see this update. For the last few decades, non-profile portraits have slowly been gaining ground across the world, and they always are more interesting than the profiles that they replaced. Here are three portraits on three Mexican silver coins from my collection that use unconventional angles:



So, just accept the Jeff, and I hope that every American coinage portrait will be redesigned similarly.
ATB Quarters - They're pretty nice but there's a lot of them. (At least they're better than the
State Quarters - some were spectacular, but some [Texas] were total flops.) Why not have more one-off circulating commemoratives, like the Bicentennial coins?
NIFC Kennedys - Good riddance to these, these things are maybe a little bit too big. Why not do something with that size? I hope to see a redesigned American half one day, maybe smaller, maybe with an interesting shape.
Presidential dollars - I like these, at least they don't all look the exact same. I'm OK with the edge lettering, although it seems quite poorly applied. The Statue of Liberty looks pretty nice, too.
Native American dollars - These are just awesome. They're actually world-class, every year they commemorate something interesting and the design is always beautiful. What an incredible shame that the newest ones don't really circulate - no matter how hard I look, I can't find any of the commemoratives up here. Please make more.