The tales series has become something that I don't want it to be, and I want to go into this saying I realize that when changes happen someone isn't going to like it. I happen to be on the bad end of the stick in this case.

I've played every single tales game in the series since symphonia except for symphonia DotNW, and all of those games (save Zesteria and Graces F) have had the same relative "Tales of" feel. In those games, you have normal attacks, then you have 3 steps of artes that can be performed in a sequence to create comboes in exchange for TP (the equivalent to MP in any other RPG). As you progressed through those games, you would eventually unlock new tiers of artes, sometimes through cutscenes, sometimes through leveling, and sometimes you would unlock artes that were better versions of previous ones that you used frequently. As you unlocked new teirs of artes, you had a real feeling of progression. When your old comboes used to be 3 normal attacks and a single arte, you now have that same combo followed by a new arte. This system made artes feel powerful, it made them feel valuable. You could mix and match new artes for different situations, and develop your own style of play. Additionally, as you progress through the game sometimes you unlock more attacks in your basic attack combo, making you have significantly higher damage output.

The Berseria battle system completely ruins all of that. The way it works now is that every attack is an arte. The TP system has been scrapped and replaced with a "soul" resource system. At the start of a battle, you have 3 "souls" in your gauge. Each souls has 30 points (there is a name for the point, but it escapes me at the moment), and your artes use a certain number of points after you use them. If you stun or inflict an enemy with another status effect, you will steal a soul from said enemy, and other enemies will do the same to you. When enemies are stunned, they are vulnerable for a time, allowing you to do massive damage, and again, enemies can do the same to you. Now for balancing purposes this seems fine, but when you are stunned, all of your controls are ripped from you and you just have to sit there, it feels awful for a system that boasts fluidity.
The ally AI (at least while I was playing) is bugged into doing nothing but attacking once and retreating. This is only a problem with the PC full version (the demo on PC and all the PS4 versions work fine). This means that in a fight against, say, seven wolves that stun, you are essentially trying to accomplish the impossible task of doing a 1V7 where you do not get hit at all, because if you do get hit you'll sit there FOREVER and get ripped to shreds as your useless party members laugh at your woes.
***EDIT*** The AI has since been patched, so this is no longer a problem.

The other problem is that this system makes artes feel mundane. Now instead of sequences of attacks with progressing strength, you are simply able to just spam attacks in any order and have them link together. Instead of everything feeling like artes, I feel like I'm just doing a sequence of different normal combo attacks. The only real progression throughout the game is that you unlock new artes from time to time while leveling. These artes are usually a bit more effective then the previous ones, making them useless after you get objectively better ones. In the old tales games, no arte was useless; sometimes they used less TP than the other artes in their tier, sometimes they hit enemies in the air, etc. Every arte in a tier had a purpose, and the way the comboing system worked in the old games made even the first arte you started out with useful to the end of the game. Aditionally, the way the souls system works, you never unlock new combo potential later in the game (as far as I've seen), so you don't end up feeling like a more experienced and skilled player, you feel likea player who has accumulated better moves.

The one thing I like about the battle system is enemy weakness chains. Essentially, if you exploit multiple enemy weaknesses in a combo you will do more and more damage throughout the combo depending on the number of said exploited weaknesses. This makes an otherwise "set the combo with the most damage to the X button and spam X" system a bit more strategic. I think the hope would be that this makes every attack have a use, but as you progress some attacks are so weak that it's better to just use a strong attack because the one from the start of the game is so weak that it negates the weakness chaining system.

Also, the gear mastering system is kind of awful. Every piece of equipable gear will give you small (seemingly pointless) skills, and you can unlock the skills by equipping the item and earning grade to learn them. This leads to a bunch of grinding for something that you're not even sure you want. It honestly just feels like it's there to pad out the game.

My main gripe was with the gameplay, but I must say the story is awful. I give it a Linkin Park out of 10.

TL;DR: If you like old tales games because of the battle system and good storytelling you'd better look somewhere else. If you like samey combat, and you crawl in your skin and/or your wounds will not heal, play to your heart's content.