I use my note 2 as a replacement for a regular paper note pad and it works amazing. I use the this daily but for longer note taking a 10 device is going to be better. I am personally planing on getting a note tablet soon.
But it sounds like u should continue using the setup you have now as you seem to have a lot of apple products introducing an android phablet to replace an IPad and iphone I don't think will be better move
My note 2 replaced my nexus 7 but 5.5 to 7 is reasonable tradeoff but 5.5 from 10 isn't imo