what does this mean? watch when the value at the address given by my_ptr changes, or watch when the value of my_ptr changes (i.e. it is modified to point to a different location) ?

gdb) watch * my_ptr

Ah ... now it's clear what is meant.

gdb) watch 0xfeedface

hmm, now 0xfeedface is not a variable but literally an address. But wait, is it? What does this mean? Watch the value at memory location 0xfeedface? But that's totally inconsistent with the semantics of "watch my_ptr". So,

gdb) watch * 0xfeedface

and once again, no ambiguity over what is going on and consistent syntax.

As for you other complaints, I've been programming for about 33 years in C and C++, and I don't recall ever needing to use a hexdump inside the debugger or the disassemble command. Which is not to say that they're not important for some work, but they are also not important for all work.