On one level, it's logical to see quarterbacks turning into offensive coordinators. More than any other player, the quarterback has to understand the role of every one of his teammates on any given play. He also has to understand various defensive looks, what coverages they translate into and what plays or options work well against them. Moreover, a quarterback has to be able to run through those options ridiculously quickly in order to get a successful pass off before taking a hit; see Chris Brown's excellent discussion of reads here for an idea of what kind of thought goes into even the simplest pass plays. That kind of ability to think on one's feet is crucial for CFL offensive coordinators perhaps even more than those in the NFL or NCAA due to the shorter play clock (20 seconds, but only running from when the ball is set), which doesn't leave a lot of time to get a new play in.
It's easy to see CFL quarterbacking experience in particular being quite valuable, as the extra man on the field on both sides changes the dynamics of both offensive and defensive plays and coverage sets substantially. NFL coverage reads can't translate directly to the CFL thanks to the presence of an extra defender, but there's also one more receiver on each play that the offence can potentially utilize. Quarterbacks who spent a substantial amount of time playing in the CFL, such as Jones, Dickenson and Crandell, have considerably more familiarity with CFL plays and schemes than most people, and that can only come in handy in the transition to an offensive coordinator's role.
However, quarterbacking experience could perhaps turn into a drawback if the coordinator relies too much upon it. It would be easy to start thinking of how they would have handled something in their playing days, and that could pose problems; CFL playbooks are ever-evolving, and approaches change over time. A play that might have worked for Jones in 2003 as Winnipeg's quarterback might fail miserably in 2011 when he calls it as Hamilton's offensive coordinator. Successful coordinators have to be innovative and forward-looking, not focused solely on what's worked before.
Coordinators also have to keep in mind each quarterback's different skills and try to take advantage of them. For example, in Calgary, Dickenson's working with a quarterback in Henry Burris who has more mobility and a stronger arm than he did, but is perhaps less accurate. A successful scheme, like the one the Stampeders ran last year with Dickenson calling plays (despite not officially carrying the offensive coordinator title), maximizes those strengths and minimizes the weaknesses; the Stampeders often focused on taking shots downfield, which made sense given Burris' power and the talent of his receiving corps. If 2003-era Dickenson had been under centre himself, they might have been better off going with a shorter, high-percentage scheme closer to what Montreal uses a lot of the time. Dickenson certainly seems to get that distinction, and Crandell and Jones both appeared to understand that in their former roles as quarterback coaches; their respective pupils, Darian Durant and Kevin Glenn, were first and second in the league in passing yards last year. If they can carry that into their new jobs, they could prove to be quite successful as coordinators.
It's also worth noting that CFL quarterbacking experience isn't the be-all and end-all of who makes a good coordinator. Milanovich only spent one year in the CFL as a player, but has presided over one of the league's top offences and turned into a hot head-coaching prospect. Barresi's Bombers did some great things on offence despite continually changing quarterbacks thanks to injuries, and he demonstrated an impressive ability to adapt to his personnel; Buck Pierce, Steven Jyles and Alex Brink are all very different quarterbacks, but he was able to drwa up schemes that maximized their strengths. B.C.'s Jacques Chapdelaine took a lot of heat for the Lions' offence's early struggles, but turned in a very impressive performance down the stretch once the Lions ditched Casey Printers and he could tailor his offence to fit Travis Lulay; Chapdelaine was a CFL slotback before turning to coaching.
They weren't the only non-quarterback offensive coordinators to find success, either. Despite some criticism, Saskatchewan's Doug Berry led a explosive Riders' offence that saw Durant lead the league in passing yards. Berry doesn't appear to have played college or professional football at all, but has spent three decades as a coach in both the NCAA and the CFL. Toronto's Jaime Elizondo played tennis in college before turning to coaching, and he did some good things with the Argonauts' offence last season, particularly in developing a run-heavy game plan (highly unusual for the CFL) that took full advantage of Cory Boyd's skills. I'd put their struggles in the passing game more down to poor performances from quarterback Cleo Lemon and an inconsistent receiving corps.
There's a good chance that Jones, Crandell and Dickenson could turn into great offensive coordinators, and if they do, I'd put at least part of that on their lengthy experience as CFL quarterbacks. However, the success of other people like Barresi, Berry and Chapdelaine proves that you don't necessarily have to be a CFL quarterback to do well as a CFL offensive coordinator. I'd argue each team's got a pretty good mind in that position at the moment, regardless of if they ever took a CFL snap from centre or not.