Wait....
You do realize that it transfers heat BETTER the tighter the fit... I.E. you want to squeeze out as much as you can between them.
So why do manufacturers use lots of thick stuff or pads? Because they need to make sure there is enough there and do it quickly. The person or machine putting it in place doesn't have the time to put it on in a precise manner, and they want to control for tolerances. Also, the margins, especially on low end laptops is incredibly thin, so while you may be thinking they should use as little as possible, the stuff they use is cheap. If just one fails due to the compound, it would destroy the profits on several hundred laptops, so it's cheap insurance. Another reason for the large thick stuff is it lasts a long time, thinner stuff may work better, but tends to not last as long.
So why change it to something else?
Older stuff doesn't always work well, and there's no way to know how well it's working other than it either being completely bad or you have another to compare it to. Checking it, ruins it. However, even if it is/was good, using better compound is not only insurance, but can also lower temps and therefore reduce noise. Yes, you may need to replace it again in a year or two, something the typical Dell owner will not do, but in exchange for lower temps and less fan noise, many of us are more than willing to make that sacrifice.
So who is right, enthusiasts or manufacturers?
Both.
Like I said, Dell and them want a quick to use, cheap solution that lasts a long time. A few degrees lower temps/fan noise is not worth the more fickle installation and higher maintenance requirements.