Well, there's also much time spent on things that players will never see. One example is that not long ago I moved the monster loot code from C++ to Lua - players don't care about that, but it allowed much more flexibility. By doing this, I had a much better time implementing a part of one of the new Season 4 features (magic items that monsters can randomly drop). There's many such internal changes happening, that from the outside, may make it look like not much is being done, but these kind of things are sometimes needed to make certain ideas become a reality (or at least make it much easier to make them a reality).Not gonna lie, At first I thought you're being lazier every season but after trying to do the stuff myself, Now I can imagine the great effort and time you're putting on Ascarus, Also yours looks way harder with the old TFS you had to optimize yourself.
A few years ago I made an attempt to move to 1.3 (a little while before Nekiro's downgrades became available), but even then we were already so deep into it with custom changes (I think Masiyah started in 2011 or 2012, I joined in early 2014) that it was just not feasible to make the switch anymore. Instead, I slowly moved Ascarus forward internally (adding the Events interface, new Lua scripting system, internal optimizations etc) - that's again something that players don't care about, but takes a lot of time. Nowadays, the "0.3.6" engine of Ascarus isn't that much different from TFS 1.x anymore, but getting to this point took a very long time.