The general term is "pole arm" and yes, even the real thing is top heavy, it's actually on purpose for lopping off heads at a distance.
Notching your blade will help with the bonding of the two pieces together. I agree model Magic is for decoration only, not support. You can add a little weight to the opposite end of the pole for balance & easier carrying. If it's hollow, stuff some fishing weights inside it & then seal the end.