I'd read a while back something, somewhere about how Regdar wasn't part of the original iconics. I've tried to track down that article many times, but can't remember anything else about it. Still, this is penetrating regarding WHY he was suddenly added in.
As to the value of iconic characters as a whole...I have mixed feelings. I was surprised to find that I did, in fact, derive some sense of enjoyment that the same characters were regularly featured in the art across the books. That said, I also took it for granted that there were stereotypes in there that would appeal to the largest demographics - it's something of a necessity (or perhaps necessary evil) when your product is a niche one, as RPG books are. Yes, Regdar is the white male that white males are supposed to identify with, and yes, Seoni is the scantily-clad big-boobed sex object said white males are supposed to lust after. I don't believe that there's any sort of sinister intent to belittle women or other ethnicities; it's just companies trying to appeal to the people who are already most likely to buy their products.
(As an aside, I've often wondered if part of the requirements for each release of Paizo's
Pathfinder was that every book has to have at least one full-body piece of art depicting a sexy woman - not that I mind, personally.

)
The real question, to me, is are these tactics inherently offensive (and harmful)? That is, is there a social effect to always showing the main fighter character as being a white male? Does it have an impact on women (and men's perception of women) when most of the females depicted look like a sex-fantasy? That, I think, is much harder to determine.