Db file sequential reads are indexed reads of a single block. If the application consistently has waits this long, the performance will be noticeably slow. If you're experiencing waits on this event you should identify which tablespaces or objects these are occurring on.
Review the raid configuration and disk speed for the affected tablespaces. Make sure that they are spread properly across high speed disks. Consideration should be given to isolating these tablespaces on their own disk. Consider running AWR reports for various times of day over the course of several weeks to see if there is a pattern of which objects have high buffer busy waits. If there is, consider setting the INITRANS higher on those objects. If your instance is Oracle applications database, changing the INITRANS setting will need to be reviewed by Oracle.