I'm about halfway through too I think, maybe a little less. The new characters and villains definitely fall a little flat. The extra stuff with Biggs/Jessie/Wedge was good. Visually the game is absolutely stunning and the musical improvements have been nice. Voice acting for the most part has been top notch.
I absolutely hate the combat system so far, it's just about awful imo. It almost reminds me of when Bethesda was asked circa 2007 why they didn't jump into MMOs. Todd Howard answered that they were a company that made RPGs with stories, and they didn't feel like they could do those things well in an MMO environment. Fast forward 10 years later and Bethesda released Elder Scrolls Online which has been kinda "meh," and they delivered Fallout 76 which has been a turd so far. Similarly, Square Enix has tried to turn the Final Fantasy franchise into a hack and slash Action genre. The character AI is about useless when you're not directly controlling a particular character. If you get attacked while using an ATB you can kiss that action goodbye because it tends to get wasted. It's not the end of the world if it's an ability that uses 1 ATB, but if it's Aerith using her signature Prayer Materia (AOE Heal) for 2 ATB? Devastating, especially considering you've wasted a possible life saving healing opportunity. It's a major flaw with this system. This issue is on top of any possible status ailments that can rob you of action, like Sleep or Paralysis. Lord help you if you get into a fight with 3 Venomantises and Cloud is put to Sleep, and the 3 enemies gang up on low defense Aerith while she tries to wake him up or heal herself.
Other than the flaws in the ATB system, I don't care for all the button mashing. It serves no purpose other than to build ATB. Action games tend to have combos and button sequences that make the combat more engaging and effective as you master it. There's none of that here, you're just mashing the Square button until you've got enough ATB to do something actually useful. Unfortunately whatever character(s) you're not playing as tend to generate ATB painfully slow and they often don't have enough action to get you a heal when you need it most. There are a few ways around this like Auto Cure Materia, but even that has stipulations and limitations. What this game really needed is some form of Gambit system like FF XII to give the AI more direction when you're not in charge of a particular character.
There are other flaws with the system, like the fact Summoning Materia is nearly useless, or the fact that the "All" Materia has been removed, but honestly the combat is just not that good at the end of the day. It's certainly flashy and fast paced, but it gets old fast. I realize there's a "Classic" mode, but it's not the original combat style. It's just some sad excuse, a sort of compromise between the existing style and the original. It does the attacking and guarding for you, leaving little for you to actually do other than picking the occasional ability. Given the popularity of Dragon Quest 11 and the fact they've worked on this project for 5+ years, I honestly have no idea why they couldn't just implement a true old school turn based combat system like in the original game. It's obvious that people still enjoy the strategy with that gameplay style, and it wouldn't have been that hard to implement. This issue is going to dog Square Enix throughout this series if they don't correct it, and Metacritic scores are already showing the game taking a hit compared to the original.