Why is the lieutenant governor roster so diverse?

[Mister Mets]

Tokenism is a valid answer.

Governors who win primaries are more likely to be white guys, and they're more likely to pick someone who can add diversity to the ticket for the most ceremonial post of Lieutenant Governor. The post isn't very prestigious, and the pool of potential Lieutenant Governors is big enough that potential Governors can find a woman or racial minority as qualified as any white guy who would take the job. There's usually a state legislator, failed congressional candidate, prosecutor, academic or state party chairman available for the office.

[Mister Mets]

As an example of how obscure candidates for Lieutenant Governor can be, there is no wikipedia entry for Charlie Crist's running mate.
http://www.miamiherald.com/2014/07/17/4240707/crist-names-miamian-annette-taddeo.html

Looking her up just gets you the 2014 Florida gubernatorial election page.
http://en.wikipedia.org/wiki/Annette_Taddeo-Goldstein

[Mister Mets]

Through 2010 IL separately nominated Gov and LG though they are elected on a single partisan ticket. The IL Constitution gives no authority to the LG other than to replace the Gov should the office be vacant and to assume any duties assigned to the office by statute. It hasn't been unusual for IL LG's to leave office midterm due to boredom and the prospects of a more interesting job.

After the debacle of Scott Cohen getting the Dem LG nomination and then finding out that he had some serious negatives in the past, the legislature utilized the provision in the constitution that allowed the nominations to be by ticket and that exists for 2014. Ironically there had been a similar debacle in 1986 when a LaRouche follower won the Dem LG nod forcing Stevenson to run as an independent on the Solidarity ticket leaving the Dem ticket with an LG but no Gov candidate. Surprisingly that didn't lead to ticket nominations back then.

On that topic, I couldn't find any information on the Republican LG nominee in Illinois.

The candidate seems to be a councilwoman from the city of Wheaton, population approximately 54,000.

According to polls she will has a very good chance of being a heartbeat away from the governorship in a big state.

[Mister Mets]

Tokenism, especially in states where the candidate for governor gets to pick the Lt Gov candidate.  Iowa and New Jersey are great examples.  Both of George Pitaki's Lt Govs were female (be design, not by chance!).

I don't think there has yet  been an instance where both the Gov and Lt Gov were females.

There are sometimes tickets like that. See Texas Democrats.

There have been 36 female Governors, so you'd assume it would have happened once.

In Arizona, there was a situation where the Governor and the next in line in the order of succession were both women: Janet Napolitano and Secretary of State Jan Brewer.

[Mister Mets]

So, the tokenism explains why Branstad, Kasich, Beshear, Abercrombie, Malloy, Pence, Scott, etc. all picked their running mates. I think I've noticed the same with the running mates of candidates like Davis (Kansas), Peters (Michigan), Brown (Maryland), Crist (Florida), Cuomo (New York), etc.

It isn't automatically tokenism if a man picks a female running mate (although I am suspicious if she has no wikipedia entry).

Cuomo picked a one term congresswoman from a politically useful region.

Brown picked a young white guy who has been a successful county executive.

Davis's running mate fails the wikipedia entry test, but she was the democratic party's nominee for Senate in  the 1996 special election, winning 43% in the same cycle when Bob Dole ran for President.

It's not a problem when a candidate for lieutenant governor provides some kind of balance. The problem is when it's someone who isn't very qualified.

[Mister Mets]

Anthony Brown picked a Jewish guy, so that could be tokenism. It might be more for balance though.

Jews are 4.3% of Maryland's population, so I don't know how much religion played a factor. It could be possible that Brown was trying to avoid accusations of antisemitism as his top primary rival, the state Attorney General, was Jewish. In Maryland, tickets run together in the primaries.

Tokenism isn't a problem if a candidate for Governor picks a female State Senator over a male State Senator. It is a problem if there's clearly a better choice for someone who could be a heartbeat from the Governor's mansion. The county executive of a sixth of the population of a state seems to be a valid contender for a less prestigious statewide office.