I'd say the point is that you've chosen a dime that has a huge mintage and are relying solely on grade rarity to say it has potential. Most old time numimatist I know don't completely buy into grade rarity on high mintage coins and see the promotion of grade rarity alone as marketers bilking the public. However, if grade rarity alone is what floats your boat then you should pursue it. I'd also say since the size of the dime lends it's self to a higher chance of finding high grades, due to it's light weight and small surface, there are probably a number of high grade business strikes out there, it's just that few want them or feel they're worth certifying. If I wanted a high grade 2007 dime, I'd choose the super low mintage satin finish one.
I'm just saying that you can't show me a 2007 business strike dime that is not all scratched and dinged up.
http://cgi.ebay.com/2006-p-pcgs-ms6...mQQptZCoins_US_Individual?hash=item4cecfa8ce4 I'd say that one is rare since there is only one of them. I am not sure but I doubt that there any 2007 biz strike dimes in ms 67