If you go to the Hotspot settings (or if you long-press the quick toggle on your notification panel, if available) you should be able to just tap the Password field and change that, unless for some ludicrous reason you have a carrier-branded version that locks that.
You should be able to by turning the Hotspot on on your phone and long-pressing the icon for Hotspot. In the window that displays there should be an option to change it. I definitely change mine to something i like. Default provided passwords aren't even fun, let alone easy to remember.
Passwords, if you think about it, aren't supposed to be 'easy'... otherwise they can be just as easily guessed. But I can see the point.
I get it, and I wish my passwords were easy to remember too... BUT passwords (especially nowadays) are not supposed to be easy. If they are, they're pretty much insecure.