The V2 Mihawk you just pulled is definitely the best Mihawk unit in the game so you don't have to worry about other Mihawks too much I guess. Raid Mihawk used to be incredibly strong/important back in the days because it was a F2P 30% health cut. TM Mihawk, who was the first TM unit ever released, was busted back then too but he can't compare at all with your new legend. V1 Mihawk is useful in very niche situations because of his specials but is mostly outdated too. About Zoro units, your Zoro is also the best one! Though Raid Zoro (the blue driven one) is pretty good for Driven and some other teams.
I get what you mean about 3D games on your phone. I'm not a fan of mobile gaming in general, OPTC is pretty much the only game that I play properly. It's not as comfortable as playing on a proper handheld or your TV console.
And yeah I totally agree with you about being behind Japan content wise. A lot of people don't like it, they say it ruins the hype, that everything arriving on Global feels "outdated". Even though it's true that there's a big hype factor when a new batch is released on JP, it's a pretty short lived feeling. And it's also pretty misleading, it definitely incites you to pull more and waste your gems. Even though the unit might not be as good as you thought or that it might be countered a month after its release (see V2 Katakuri).
On Global, we can make much more rational decisions about pulling/saving, we can also see the new unit longevity/mileage. And Bandai Global does drop some surprise legends at times, to keep things exciting for the players. Like we Inu/Neko, V2 Whitebeard, Jack, V2 Sabo etc first.
Yeah
Luffy/Law is the next big legend most people are waiting for. Everything about them is busted : their CA in dual form is 4.5x (tied highest with V2 Whitebeard but without the health restriction), their special is a 2.5x orb boost for everyone (highest out of any unit), their swap ability is insanely good (they will always get a matching orb, will go through barriers and are boosting themselves by 2x). And most importantly, they are a rainbow lead so you can use any class/colour in their crew. That's why Snakeman is so good. It means they have access to the best subs. Obviously you still need to build your crew properly, make sure your subs specials complement each other. No point putting V2 Mihawk as sub if you're not using other Slasher units since his special only boosts Slashers. Luffy/Law are not crucial though but they will see a lot of play after their release.
And then you have from the same batch
V2 Big Mom who is absolutely amazing as a sub (not so much as a captain). A 3.5x chain multiplier is the highest in the game and she gives a huge attack boost to your whole crew based on HP, something only one other unit in the whole game does (and it's an outdated unit no one uses). People were unsure about her at launch but since then she's in a ton of teams on JP for tough content. I use her all the time.
And then a couple weeks after those 2, we'll get
Koala/Sabo who are the 2nd best leads in the game imo. They might not be as strong as Luffy/Law number wise but they boost two very good classes (Free Spirit and especially Cerebral, a class with a lot of amazing units) and they are the only unit in the whole game who get rid of a very annoying debuff
entirely. And that debuff will be widely used by Bandai in future endgame content. Not to mention their swap ability is even better than Luffy/Law's, getting rid of two debuffs and boosting their whole crew colour affinity. Plus your dual Inu/Neko legend pairs up very well as a sub for Koala/Sabo since they boost Cerebral orbs by 2.25x while Koala/Sabo boost their attack by 2.25x.
And in the following batch we'll be getting
Shirahoshi/Mansherry who are just the best utility unit in the game. They will reduce any two debuffs of your choice by 10 turns, which is often enough to get rid of them. Being Striker and Cerebral they will fit plenty of teams but they are so good that people even bring them when they are not boosted just for the debuff removal and heal. I didn't expect to use them as much as I did when I first pulled them but they make my life so much easier, I just bring them for most content when I go in blind. Vivi/Rebecca from the same batch are pretty good too, I don't have them but I see a lot of teams with them.
And then you the Stampede batch with
Bullet who is an absolute monster, he "only" boosts 3 colours but it's a flat 4x boost all the time, while Luffy/Law and other dual units only boosts for 3.25x or 3.5x until they are in their dual form for 3 turns. Two of the 3 types he boosts have access to incredible subs too. And Bullet unique ability is that he inflicts rainbow damage, so despite being a STR unit, he'll always deal double damage against any other colour, even QCK. Coupled with the fact he boosts his own attack by 4.75x, just finish your attack chain with him every time for incredible damage.
As you can see, the next 4-5 months are full of busted units and each of them should release with a 2x legend rate sugo. I didn't even mention Stampede Luffy or Kaido. That being said, the powercreep is still relatively minimal, in the sense that you can still beat everything with Snakeman and clear a lot of stuff with units like Sanji/Judge, Barto/Cavendish, Carrot, Capone. Some of those legends can pair with/leech from the newer ones too. But yeah if you manage to pull one of those future legends, you'll be set for a while.