I wouldn't go with the G5 because I'd miss the S-Pen (and because when I tried the G4, I just couldn't love it next to a Note 5), but either wait would be smart. New flagships mean harsher competition for 'older' models, which mean that even if you still want to go for a Note 5, it's likely that it'll have some sort of sale or better deals or financing.
If you're up for an upgrade now, it might be too long of a wait for the Note 6 though haha. My hands would tingle if I had to wait that long!