GDB can be extended using Guile Scheme. I am pretty ignorant when it comes to GDB, but I've seen people write Scheme extensions to help with V8 development and inspect certain C++ data structures more easily.
...I put in the star to say that the Python API didn't count, but forgot to actually elaborate on it.
So when you say it's not good I guess you want to do other things (which?) - or else you mean that it's messy (if so I ought to say that I've seen much worse and in relative terms I'd say gdb's API is rather lovely.)