I've been seeing more transdermal creams being used. I know of someone who started using it, prescribed by his doc, for blood disorders. I haven't followed up with them to see how well it's working. Dr. Kendall Stewart has quite a few videos on using topical creams as part of restoring the neuro-immune system. He has also formulated them. You can look at his products and videos at http://www.neurobiologix.com/

They're pretty expensive.

The body has been biologically designed to get vitamins orally.
The first pass thru the liver, may be important for some of them to be activated.

Anything transdermally therefore, will not pass thru the liver first.

But it is difficult to say, with proof that certain things would be better (or not) transdermally.

Some things like racemic lipoic acid are not absorbed well, but the new R-form stabilized is well absorbed however.

And yes, transdermal products tend to be very expensive.

I know for myself that the magnesium in cream form works far better on specific target problems than oral. It takes down swelling for me, and also improves specific muscle problems etc.

But it is difficult to extrapolate that utility to other nutrients.
Perhaps in people with thick blood or poor circulation the vitamins would be useful in a transdermal base, or for those who cannot swallow, etc. People with malabsorption issues too, like Celiac may benefit more than those without that problem.