He won't be fired this offseason. It's not a matter of should or shouldn't. He won't. He can't. That being said he's dangerously close to dead man walking status, with two loosing seasons in 3 and throwing the dc under the bus stops being effective especially when the O is as bad as it was this year.
That being said what makes it hard to replace Johnson is that if we fire him, there is little chance that we go with another real triple option coach. Monken would probably be the best bet because he's familiar with the system but has shown a willingness to adapt it that Johnson hasn't. But that would make sense if Johnson retires. Not if he is fired. Otherwise something like Chad Morris, Charlie Strong, or a high profile assistant, Venables would be what we could look at. IMO we'd be better of looking into the FCS level and try to identify the best fit for us. Mike Houston would be my pick from what little I know about that level.