False alarm with Shadow Fight. Seems I've gotten used to blaming the device that I forget about regular Android issues. It seems that a malicious app, some kind of "TcheirekSkipjacklyService" was running in the background while Shadow Fight was running. I got rid of the app and now, all though the device still gets hot, Shadow Fight doesn't slow down half as much. While there is still some slowing, it's not too bad.
I still haven't deodexed anything at the moment. I'll try more xposed mods to push the limits. So far everything is still good. Updates for games are installing as they should. Assassin Creed Identity still giving issues, but it's given many people issues so I'm not too concerned.
Still using 6.1.1 international. I'll update if I have anything of value to offer.
Guess there are still a few more issues to solve. The slowdown seems to have many possible factors, and is possible that the storage I/O performance might be the case, since the phone performs poorly with both internal and external storage. I've been using SAMSUNG PRO series microSD cards that can naturally do around 80-90MB/s R/W as tested with a USB3.0 card reader, but on the phone, neither the internal storage nor the microSD card can do beyond 10MB/s unless a cache hit occurred. I'll try tweaking a bit more with Kernel Adiutor myself.
The only major issue is the audio... while the SoC has a good DAC its driver (or perhaps the system's audio services) performs poorly and gets interrupted easily by external factors. Notably that the launch sequence of certain games (well I dunno what they do during launch behind the scenes), even phone calls, would stop or kill any running background media playback in W3D regardless, while such had never happened with 78P01. I even started having issues with my usual online radio player (it's a live stream) suddenly stopped with a "Failed to play audio." toast notification that came from nowhere, even on foreground.
Also, it seems I'm able to run the latest Android Wear on W3D as well... though I dunno if I'll still need to configure the watch using the 1.3 version which was the one that I was eventually able to successfully connect the watch.
Unfortunately, this phone and probably the MT6595 SoC in overall was hardly popular to the modders compared to MT6592 which 78P01 was based on... I tried placing
Meizu MX4's CM12 port into the phone after
following the first few steps of this guide, initially it could not boot at all, though I could not blame anything as the MX4 port's kernel version was a bit higher than W3D's stock one (3.10.35).
If I had time I might try all the steps in the "Fixing Bugs" section, but even so, the resulted ROM may not be in anywhere near the word "usable" (especially given the soft BACK/HOME/MENU buttons and the built-in gamepad functions, something that rarely exist in mainstream phones nor ROM ports), and that the phone is currently my daily driver and I can't afford to have too much downtime with trying these on.
As for 6.1.2... I think it's optional to actually install it. Apparently the behavior of auto-forbidding all newly installed/updated apps from auto-starting is exclusive to the Chinese firmware, including earlier ones. In International firmware the phone would let the user decide what to do instead. Also, for some reason I find that some apps (Including Kernel Adiutor) still would not auto-start even after I allowed it in Settings and have properly turned on the "start on boot" option inside the app...
By the way, I haven't tried, but one can try manually sideloading both the KeyAdapter.apk and KeyAdapterResForISeries.apk from the 6.1.2 firmware (can be extracted from app.img in its update.zip, using
ext4 unpacker) to get access to the L2/R2 buttons... If the new firmware update did not update anything besides that, that is...
Still, without kernel source code it won't be easy to improve the phone's experience any further.