I would rank Hartley as one of the better coaches out there. There is one single problem with Hartley - he is very hard on players, and it wears thin after a couple of seasons. He is probably the most old-school tough coach left. However, for those that say he isn't good at coaching, all I can say is that you have nothing to base it on. He has won a championship at every single league he coaches in - NHL, AHL, Swiss and now in the KHL finals. That's a pretty good record. It also isn't like he is only joining powerhouse organizations either - he joined ZSC Lions and they weren't expecting to do much, and suddenly they win the championship. His tenure in Calgary was, in hindsight, absolutely awesome. Flames played some very exciting hockey, and it made that rebuild so palatable. Even pushed the Flames to the 2nd round in year 2 of the rebuild - that was utterly amazing.
As for his systems, whatever he implements he is incredibly demanding. He forces his players to work. You have a role on the team, and you better fulfill it. As an example, when Stajan and Backlund went down during Monahan's rookie season, Monahan was becoming a defensive wizard. That's good - Hartley demanded his players be strong 200ft players. However, he took Monahan aside and told him that it was great he was being so defensively responsible, but he was cheating too much on defence and his offence completely dried-up. Same thing with Backlund.
People assume that Hartley's system is all about unsustainability and 'cheating' on defence, but that's not quite accurate. The Calgary Flames under him did not have the horses to really play a strong puck possession game - not without offence completely drying up. His system was reliant on players covering for one another in the offensive zone. Flames were REALLY good at this, actually. If someone didn't cover for a pinching defencemen, you better believe that the player (and about 20 rows of fans) would hear about it. His system was all about limiting shots to the outside, and trying to limit high danger chances while transitioning lightning-quick to create high danger chances for themselves.
That team was not deep. They were not talented. They exceeded expectations for 1.5 seasons, right up until Hiller started allowing goals from low-chance shots. When Ramo returned from the AHL (after also allowing a great deal of outside shots), Flames were looking like a team that was once again going to make the playoffs... and then Ramo got hurt and they imploded. They were a team with AVERAGE (in their playoff year, literally the middle of the pack) in terms of goaltending.
Hartley's tenure on the Flames ended poorly that year - but a lot of it was centred around poor... no, abysmal is a better word - goaltending. Every single night you saw a team that worked their butts off and exceeded expectations. They were entertaining as hell to watch as well.
I would think Hartley would do really well on a team that is failing to meet expectations. You sometimes want a hard-assed coach to come in and change a culture. That's what he does best. In my opinion, the greatest leader on a team is the coach. If the coach can make all the players buy-in to whatever system he implements, and makes them all play hard in that system, a team should experience a certain amount of success. That is probably Hartley's best lesson as a coach to a team - if everyone buys-in and works hard, you will be surprised at what you can achieve. He has a history of getting teams to do just that. Every team outside the playoffs that SHOULD on paper be better - if I am their GM - I would be seriously looking at signing Bob for 2 years and teaching my guys what hard work means, and how sometimes brutal it can be to have a coach this tough. I would hope my team would snap out of any country-club atmosphere it seems they are in. Oh, and he is fantastic with young players. Outside of Baertschi - who seemed to stick out like a sore thumb with his consistent lack of compete - every other Flames young player looked really damn good. Gaudreau, Monahan, Brodie all broke out under Hartley (with Brodie never looking better than under Hartley). Colborne hit 20 fricken goals, and made a huge mistake in not accepting Treliving's offer. Bennett was looking like a monster in the making under Hartley. Backlund really came into his own as a 2-way player. Mark Giordano broke out as a top-pairing guy under Hartley. The list goes on. That's a good coach, with the caveat being that it wears on the players and it won't last. But for a culture change? I still think Darryl Sutter is probably #1 on that list of a coach that can come in and completely turn a team around. Hartley is probably #2, but is even a more hard-assed coach (though I rank Darryl as being a much better overall coach).
All I know is that after watching the Gulutzan-era coach, I started pining for Hartley again, and not just in the standings. You get an entertaining team in Hartley. That's important. It is unpalatable watching your favourite team playing incredibly boring hockey unless you are a bona fide contender. If you are not getting the wins coinciding with that boring play, you start wondering if it would be more fun to see how many times you can poke yourself in the eye during a game.