I think that's really the wall right there. Blotter is really amazing. Although its the behind the scenes work it is really what gives a lot of the underlying functionality. Python nor Matlab has anything as nearly as robust as either of those 2 packages.
To be honest the backtester of quantstrat or zipline or any other tester for that matter are basically glorified loops. Its really the underlying functionality that makes R/quantstrat using blotter/PerfA shine.