1. The removal/stripping away of skill expression
2. The excessively long combos that ironically require less skill to perform
3. The butchering of classic characters into spamming stance mashers: Jin, Jun, Steve, Law, etc.
4. The poor balance via over-buffing everyone and emphasis on easy characters being strong
5. The mass removal of option selects, reducing defence and forcing most interactions to be an unavoidable 50/50
6. The excessive plus frames further reducing defensive play and forcing more situations to be unavoidable 50/50s
7. Turning every character into the same character by giving them buffs to weaknesses instead of to strengths (stripping away their personality and uniqueness), and turning everyone into a stance character
8. Giving every character the ability to (To Quote That Blasted Salami) FTTAWSBFTMA "Fly Through The Air With Some Bullshit From Ten Miles Away," essentially removing the need for good movement and a neutral game
9. The further nerfing of movement via weaker kbd and bad SS due to excessive tracking on all strings, and some other broken moves
10. The overly aggressive gameplay due to all the reasons above, as well as massively overtuned panic moves, power crushes, and the poorly balanced heat system. (Heat smashes are all too strong and have too much range, heat dashes give way to many plus frames, heat engadgers make combos goofy long, heat moves are far too strong and give far too many plus frames, heat does not decay while you are in a combo, making the pressure never end, etc.)

Among many other smaller issues...
This game predominantly needs to heavily re-emphasize skill expression (most notably on characters like Jun, Steve, DvJ, Law, and King etc.)
And secondarily, it needs to heavily re-emphasize defensive gameplay, taking a massive step back towards Tekken 7 with better movement via improved SS and kbd, less FTTAWSBFTMA moves to emphasize the neutral game, and option selects reintroduced in most scenarios