If you didn't think Samsung is going to experiment with all possible device sizes, then there is little doubt now. A new rumor says that Samsung will unveil a new 5.9" smartphone in the second half of this year. That's right about the time when the Note 3 is supposed to be announced and released. However, some earlier rumors said that Note 3 would be 6.3". If those are true, does that mean Samsung will also release a smaller "Mini" version of Note 3, just like they did with Galaxy S3 this year?
Personally, I think the 5.9" size is a lot better for the Note 3, for a couple of reasons. First, it's obviously smaller. I think 6.3" is going too much from "phablet" into "tablet" territory.
The original Note, which was criticized by many for being too big, turned out to be quite a success, because people wanted something that is pocket-able, and could replace a tablet or an e-reader for them, as well as being useful for taking handwritten notes.
Note 2 had a slightly larger 5.5" screen, but it was more compact, and 16:9 instead of 16:10, which made it only slightly taller than a Note but also a little less wide, even with the larger screen.
A 6.3" Note 3 on the other hand should be significantly bigger than a Note 2, no matter how compact they make it. That means it might break that promise that it's "pocket-able". A 7" Nexus 7 is barely pocket-able in the back pocket of jeans, but it's definitely not in front. I don't think a 6.3" device would fit well in the front pockets either. That could make a 6.3" Note a lot less interesting, because if it's not pocket-able anymore, why not just go for a Nexus 7 or a Note 8.0 instead?
The second reason why I think a 5.9" Note makes more sense if also because of a marketing one. The 5.9" would not only be smaller than a 6.3" one, but it would also "sound" much smaller. It's a psychological trick, for the same reason many more people buy something that costs $2.99 than $3.00. A 5.9" Note still sounds like a 5" device, rather than a 6" one. That might make a lot more people buy it. It would also still be significantly bigger than a 5" Galaxy S4, to make people prefer it over the S4.
In the end what will matter most is if Note still fits that promise of having the "maximum screen size that still fits in your pocket". If they can squeeze 5.9" into a Note 2 body, or even one that is slightly bigger, I think they will succeed with it. I'm a lot less sure about a 6.3" Note. And if they do that, they might want to release a smaller 5.9" Note anyway, just in case.