Some things that would go a long way towards making this team a legitimate Super Bowl contender.

1. Aaron Smith is out and Keisel is banged up.  The healthy  D-line and OLB need to get on the same page a little better to get more pressure on the passer.  This is not just in reaction to the last game.  Last year the OLB were living in the backfield,  this year they're struggling to get consistent  pressure although the total number of sacks is fairly high.
2. Learn how to run left in addition to right.  ( a lot to ask I know).  Sometimes you can just run right and  impose your will and the other team isn't good enough or smart enough to stop it.  You need a backup plan if that doesn't work.  The Ravens and Pats both put another NT versus our right side and it's been pretty effective.  Pretty much the only running to the left are the FB dives off of the pony set.
3. Learn how to play pass defense without giving WR an 8 yard cushion.  Again, not saying you need to play this way all the time.  A lot of offenses are not good enough to dink and dunk down the field as evidenced by the Steelers formidable scoring defensive stats.  To be a legitimate contender we need to play man more against the best QBs.  When the team has gone to man in the 4th quarter of losing efforts against NO and NE it's been pretty effective.   Man coverage also allows our safeties to freelance a little more.  Polamalu and Clark haven't impacted a game lately because they're playing deep safety over top of corners that themselves are basically playing as an over the top safety.
4. Play calling and execution versus the blitz.  Expect to see a lot more blitzing this year.  Hot read receivers are not on the same page with Ben.  I saw the team actually execute a slant pass in the 4th quarter.  Not sure if Arians picked that idea up via Twitter feed or what but it worked.  Learn to execute short routes to take the edge off pass rushers.
5. Roll out Ben.  He's effective on the move and it also takes something off the pass rush.
6. Learn how to take a defense that is lights out verus the run and weak versus the pass and make it, on occasion, more balanced at the expense of run liability.  I think in practice this might mean taking another big man out for a safety or small backer to play the under pass routes.  Harrison and Woodley do an admirable job but there is room for improvement.  Even when we take a lineman out we still basically have 4 big guys stacking the line versus the pass.
7. Jeff Reed may not be drinking enough.  He just doesn't seem right.  
8. Stop using Spaeth as a blocker.  He actually caught 3 balls in the Cin, NO games.  He's a big target with good hands and he can't block.  Either throw him the ball or put another OT in there.
9. Minor point here...  Mendenhall is maybe the most consistent player on offense besides Ward but he needs to stop turning around when he's obviously going to get hit.  I realize that he does this because that's the last time he can turn a spin move on that given play (so what the heck right?).  In practice he turns around the backs into the tackler.  If he keeps his head facing forward he can have a more glancing blow perhaps and also he can drive his legs, getting some additional yards and punish the tackler somewhat, maybe you even break the tackle...  When you turn around at the tackle, you've basically thrown in the towel on the play.
10. Consider making ARE inactive for a couple games to get Antonio Brown some experience.  ARE has the lowest receptions / targets ratio on the team and he's not a long term solution or a dynamic play maker.