Over the past year and a half Samsung has used probably the biggest differentiation feature for tablets (and very large phones) among all tablet and smartphone manufacturers, including Apple. That feature is of course the S-pen, an active pen that is much more accurate than a capacitive pen, which I've personally found to be barely more usable than your finger, in general.
With rumors about a whole bunch of devices supporting the S-pen this year, this news of Samsung buying 5% of Wacom comes as no surprise. The S-pen was made in partnership with Wacom, which is the best active pen maker on the market, so of course the S-pen is as good as it is. Buying share in Wacom ensures that Samsung will have a long-term relationship with Wacom, and they should be helping them make such pens for years to come.
Contrary to what Steve Jobs said years ago that if you need a stylus, you're doing it wrong, I believe the stylus, or at least active pens are making a come back into the mobile market. The difference between now and then, is that back then those PDA's would've been very hard to use without a pen, and they needed the pens to work properly. But today any touchscreen device works very well without a pen. However, the active pen can be very useful for things like drawing and handwriting.
Some people may like to take notes by writing them down on the screen, as they would if they had a paper notebook, or they like doing school work on these devices in this way, while others like to draw on them, especially people with an eye for drawing and design. So Samsung is really exploring that part of the market.
I think we'll see a lot more Note-like devices in the coming years from Samsung, and all of them from 5" to 10" will probably have an S-pen, especially if the price of the S-pen becomes almost negligible, and they don't have to worry about adding the pen but compromising on other specs, such as using a lower resolution than they should, like in the upcoming Note 8.0.