Yes, it's all we have to go on for now, but some teams make drastic improvements in the span of a year and others drop off horribly. The Atlanta Falcons were 13-3 in 2012, so they helped make the strength of schedule for their 2013 opponents tough. But the 2013 Falcons were 4-12.
Also, a team has a bearing on the perceived toughness of its schedule. The Titans play the Colts twice annually. Tennessee lost that game twice in 2013, helping boost Indianapolis' record to 11-5. That 11-5 helps make the Titans' strength of schedule in 2014 tougher, but the Titans had a hand in creating it.
The only team with an easier strength of schedule in 2014 is, incidentally, the Colts. Indy's opponents were a collective .430. As I said, the Titans had a big hand in that.