This topic has some complexity.
First, there is no “they”. Illfonic might consist of some 100 developers (including the artists) of which 98 might do an outstanding job including testing. E.g two people who cannot or do not want to perform resp. test well are absolutely sufficient to lead to a patch disaster…
So, in the end, it might not be a problem of the developers but one of the management, if you ask me.
Second, it is unfortunately somehow common nowadays to let the users do the testing… It is obvious that in some aspects that might be done here too…
Third, the complexity of real-time-multiplayer-applications-via-network is enormous. You even cannot test everything here.
I would say, PHG in general is an absolutely great game working quite well in most aspects - considering the size of the company and so on. But, as I said before, it seems so, that those people, who did the design of the data structures (alike controller settings or loadout), might not be the best part of Illfonic…
I come to this conclusion, as the errors in the last patches nearly all seem to be ridiculous from my POV :) In properly designed, object oriented software, they even should not be able to happen - if you ask me…
But the usage of proprietary static data structures can easily have the effects we all experienced. Said usage is not state-of-the-art software design, from my point of view.
It would quite be interesting to hear an official statement, whether said data structures indeed ARE proprietary static ones… :))