Scioscia actively cost his teams wins with that decision btw, since there were potted plants who offered more offensive promise than Mathis.
Swihart tracks to be - not an adequate defender - but a good to very good defender who might be athletically overqualified to catch. That is a different kettle of fish. I like both guys btw, but if you have two quality young starting catchers, hoarding them is not the best way to make your team better.
Book on Cecchini is not written yet, but the move to AAA definitely slowed his momentum. If he is the best 3B prospect in the org, it's because he is close to the bigs. He can probably be a solid 3B for somebody, but he has very much moved (if he was not there already) into the "trade currency" bucket.