Very easy answer for me. Upgrade the offensive line's pass protection. I am looking at Iupati and Goodwin. One or both of those positions need to be upgraded to give Kap more time in the pocket. I love Iupati, but he is not an adapt pass blocker. I'm trying not to go off just the emotions of the loss as there aren't many Olines that do well in SEA.
The NFC West is loaded with good Dlines. If we want Kap to progress as a pocket passer, then he needs time in the pocket. To me, this is above getting a deep threat, although that is an important second.
Also, get some better cover corners and the 49ers will be good to go in 2014.