The problem with "may issue" is that it puts too much power in the hands of individual cops. The temptation to sell the permits for campaign contributions, or issue only to major campaign contributors, or issue in a racially biased fashion or worse (yeah, we'll get to THAT) is just too high.
Examples:
* Former Sheriff Baxter Dunn of San Joaquin County Calif was jailed under Federal corruption charges. His partner in real estate fraud pulled his Dunn-issued CCW-permitted gun on Federal agents. Feds were SO not happy over that one.
* The current Federal corruption charges against former Sheriff Carona of Orange County Calif includes selling permits under the table for $1,000 a pop. (Carona also had a weird "fetish" over gangsters, dressing up like one for halloween(!) and hanging out with real ones. There's strong hints he issued permits to same...)
* A member of the NYPD brass in charge of gun licenses was fired after he was found to have scored backstage passes, limo rides and general "hangout rights" with the band Aerosmith - the two frontmen for which he had issued permits to despite their WELL known history with drugs (pretty much everything imaginable and many that aren't).
I could go ON and ON and ON with this crap but this actual police report will summarize nicely:
http://www.ninehundred.net/~equalccw...escopapers.pdf
It gets worse. Inevitably, this kind of "policy" becomes known in the department. In the Colafrancesco case above, a disgusted deputy leaked the report...and the officer that had taken the statements in there suffered horrible retaliation (even though he wasn't the one that leaked it). This crap has a corrosive effect on ALL aspects of law enforcement.
Issuing to anybody who can pass objective standards has a strong track record in at least 38 states. There's no need to get more restrictive and no sane way to do so without running into the problem of "laws by men, not laws by law".