If you think that they actually take any feedback from the community then you clearly didn't pay attention.
Nobody from QLOC (company that handles PC port) even bother to write anything on Steam. You get only WB guys who use 2 pre-written replies as copy / paste to anything people write there.
And this Beta serves only one purpose -
to get PC player hype about the game again. It has no other point. GGPO in it was tested on consoles ages ago and its solid for quite some time, there is no technical reason to test it again on PC.
Also do you think they would gave us whole roster instead of like 4 characters (console beta started with 4) if all they wanted to do is test online?
They wanted people to get hyped about the game AND "new" (KP2) characters. So when the update / XL is out on PC people would buy XL / KP2 pack (if you already have MK X).
And why soon? Coz when the beta will end, people obviously will stop playing it - if they take too long with the release many people will just forget about it (casuals) or get annoyed and that's not good for the business. And imo the game (XL on PC) is ready for quite some time now, they're waiting only for the release of final patch so it will be the same on all platforms.
Also so its absolutely clear they're doing MK XL on PC mostly coz they want to sell IGAU 2 port on PC at some point after console release next year (probably close to it end, just like they did with IGAU).
It's business, not rocket science.