The need to keep your website's management under control is clear. The need to homogenise the design is not.
I made that word up, of course. But most websites are designed to a standard template, and it's a serious problem. What happens is that one page needs certain links, another page needs different links, but because every page uses a standard design, all of those links get shoehorned into every page. And the majority of them are simply irrelevant on many of the pages where they appear. The message is drowned out by unnecessary "page furniture", and the graphic design is made dull by the need for splash pages about important products to use the same headline and body copy type sizes as the page about the company's terms and conditions.
When we set up AdWords campaigns for clients who have a specific aim (e.g "I want to use this campaign to get downloads of my blue widget brochure"), it's not unusual to decide between us that there's no suitable page on the company website to send people to. So we make up a special landing page just for the AdWords campaign.
Making up a special page is not a problem. But why isn't there a page which is suitable? If this initiative is important enough to advertise, why don't everyday visitors to the site get presented with the same offer?
Turn the idea on its head. Select a random product in your company's range, and think creatively, without restrictions, about what an ideal web page introducing that product would look like. I suspect the answer would look more like a magazine advert than the web page you have at the moment. What are the differences between what you'd like, and what you've actually got? I bet the main one is caused by the requirement for pages on your website to look the same as each other. Is that really necessary? Most website content management systems allow alternative templates to be created and used, and these could be quite simple, almost blank canvasses. The need to keep your website's management under control is clear. The need to homogenise the design is not.