I'm fine with them merging at this point. There's literally no difference between the two other than the S series feeling much more comfortable in the hand and not being able to insert the S-Pen. When the Bluetooth S-Pen comes out, just let it be charged wirelessly or via the USB-C port in the phone, and we're good.
If they going to merge they better keep Note line's wide/square corners and lot better if the s pen lived inside.