I think the 5 is the first one they started taking sales seriously on, trying to mainstream the line.
However, they also undid a lot of what to many Note fans defined the Note line. Making a big screen and packing it with lots and lots of practical, daily-use features, plus a few new gimmicks that were a bit experimental and might or might not end up in the more consumer/less geek oriented S line to follow.
Obviously differing people have different desires, but looking at the differences between the Note 4 and the Note 5, my feeling is that they redefined the Note series that round to be "Galaxy S, now with S-Pen!" rather than "full-on productivity megabeast of a phablet" - which was probably great for sales, but was also disappointing to a lot of us looking forward to two distinct phone lines from Samsung.