OP: Do you seriously think a product development manager has even the slightest interest in answering (potential) customer request emails? Do you think they have time for that? Do you think they get paid for that? If so, you need to look up the difference between 'customer relations' and 'product development'. At best, they'd redirect you to sales or some branch of their customer service department. If not, they'd just mark it down as spam.
Now, assuming someone knows, is friends with, or has a business relationship with a Dell product development manager: what do you think would happen to that relationship if they gave out their email on a public forum? It would end. And not in a nice way. Would you like to be on the receiving end of the email address that is the top result if you google "Dell manager email" or something similar? From every pissed-off customer, every tech-illiterate user, every smartypants who thinks they can do their job better? I didn't think so.
While I'm not opposed to your intent at all (and I do think most laptop manufacturers make a lot of really weird/wrong choices), you're not getting that info. Not from anyone. Don't be daft. It would be more constructive to contact Dell customer support and ask them to implement some sort of product feedback/feature wishlist survey thingamajig. That might actually get you somewhere.