Multisite vs separate installs in subdomains.

Hi folks, more grist for the mill

Two questions, related:
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Question 1.
I work for a pharmaceutical company, and we promote our main company, but then each of our medicines is sort of marketed individually but we want to make sure people know it's us who made it.

For example. Pfizer makes celebrex. .. But they seem to have a separate site for Celebrex even though it's only about 20 pages.

I want to use subdomains at the start so that our products are sort of linked to us.
Like celebrex.pfizer.com. Seems you get both brands in the bang for the buck.

Now, my predecessor started building very thin sites for our products and they don't get a lot of traffic.

I'm thinking it's the perfect time to move our http://www.SUBPRODUCTA.com individual site that gets 10 visitors a day to SUBPRODUCTA.mainbrandsite.com.

Then map the http://www.SUBPRODUCTA.com existing url to the subdomain.
Seems to make sense from both an organizational, branding and SEO standpoint.

Wouldn't google rather have a strong, interrelated brand site with sub brands than a bunch of sub websitees?

QUESTION 2

Now, I can install these sites on teh subdomains as either a MULTISITE< or individual installs.

I'm worried that a multisite might get too big and unwieldy, but then again, EDUBLOGS does not seem to.

We launch a new product every 6 months and will be adding a national doctors directory. So the directory would go an a subdomain too.

Is it too much weight for a multisite?

Thanks!!
Mark