Winning in Seattle and then against the Patriots in the Super Bowl would've been very tough. I think we could've beaten the Seahawks but it would've been an extremely physical game and I don't think they would've been able to turn around and beat Brady, not with the defense we had in 2014.
That 2014 defense was opportunistic but they lacked in talent overall and were aided by our dominant running game. While I'm sure Murray would've gotten his against New England and bled the clock a bit there's no way the offense would've run complete roughshod over them, at least not to the point where we would've been up by so much that the defense could've cruised by against a prime Brady with a DL consisting of Jeremy Mincey/Henry Melton/Tyrone Crawford/George Selvie/Jack Crawford/Nick Hayden and a rookie Lawrence.
Ultimately it would've been a close game but I can't see us winning a Super Bowl against a prime Brady with that DL/pass rush unless we were gifted a few turnovers and played an otherwise clean all around game.