SciPy's solvers cannot handle events which are nearby, most return codes aren't documented, you cannot run the wrapped solvers in stepping control mode, you cannot give it a linear solver routine, etc. So it wraps established solvers but still only gives the very basic solving feature of it, and most of the details that made the methods famous are not actually available from SciPy's interface.

And it wasn't Python 3 for pydstool. It's SciPy 1.0.0. Some of the recent maintenance for this stuff has actually come from the Julia devs though:

https://github.com/robclewley/pydstool/pull/132