Can a querystring look spammy and cause a problem getting indexed

[branning]

We're having a lot of trouble getting our product pages shown in the regular index, they're all supplemental (probably due to dupe content issues which hopefully has been resolved after following the excellent advice on this forum over the past year) but although we're spidered daily new URL's just aren't getting shown after waiting for several months.

I was wondering if our URL structure was possibly causing problems.

Instead of using multiple variables in the query string to feed our dynamic product page we use a single variable which holds all the information such as productID, categoryID, product name etc. so it condenses down to a single variable separated by a hyphen which allows us to split them up into their component parts on the product page.

e.g.
?productID=123&categoryID=2&sort=&prodName=Blue_Widgets&page=1
becomes
?product=123-2--Blue_Widgets-1.

Any comments on whether this method would now look spammy or throw a red flag for Google and is possibly affecting our chances of being shown in the main index again.