I am so tired of all that midnight blade bull* regarding how OP he is that I won't even bother to argue with people who complain about it, especially now with what's been going on lately with the Immortal teams (that are truly a bit OP considering the rest of the ninja we have). I will just say, MB isn't OP, he is as he should be, and people should learn how to counter him. It's not even that hard. For once, you have these immortal teams, second, it's so easy to counter root teams using wind main's sand dust that removes ALL buffs and shield from 3 enemies (thus, eliminating root). You also have GNW temari that does that (albeit from round 2), mifune (from round 2 and only for one char), water main's skewer mistery, etc. Learn how to play before you start complaining!!
That being said I would like point some things out, to give some hope for people who (for a very good reason) believe that the immortal teams are tremendously hard to beat now.
These are only my speculations that came from *yzing a few ninjas that will probably come in the future. I'm not 100% I am right. If I make some mistakes in describing their abilities, please correct me.
1. From what I saw, Han removes all buffs and shield from the enemy (so no water boost, no healing tips, no medical sage boost from tsunade, no double standard from Yo, no boost for 6 tails from Killer Bee) etc.
=> Dramatically reduced healing abilities and reduced damage. So no more getting back to full health when you were almost dead.
2. Roshi is a powerhouse and does *loads of damage from both his mistery and chase. Every taijutsu standard against him means ingition, and his chase causes massive damage and ignition to 4 enemies as well (it will be hard to trigger it though, since it requires a 30 hit combo). I will asume that all that ignition will slow down the healing and roshi's passive (that boosts is ninjutsu every time he gets attacked) will provide enough damage to eventually kill them. This also will depend on what other ninja's you have in you team that might do crazy damage or some form of crowd control as well. However I am just speculating here, I may be wrong.Of course, there is also the downside that they are super rares and harder to get, but hopefully the pull rates will be decent and a lot of people can get them.
For now, we indeed have very few ninja that can help us defeat these teams. I for one, succesfully manage to blitz them in most cases (depends on my luck with launching the criticals), but ONLY IF they don't have more than 5k higher BP than me(in which case, he is a bit too tanky, and as it happened loads of times, the enemies might remain with about 3-400 HP and gets back to full health). However I do own a not very common ninja.
Other options would probably be a combination of Hashirama and Sage Jiraya and another ninja with some form of cc, since hashirama gives 2 immobile per round (just need to be lucky not to hit the immune characters) and jiraya provides the ignition to slow the healing down. As main char, fire would be useful cause he has the mirror return thing that will reflect the chaos tsunade gives on her mistery. This could prove extremely helpfull.
I won't mention possibilities of teams with susano'o brothers cause so few people have them and it won't help answer the question of this post (plus they don't really work so good against these teams either).
So, I have hope that when the jinchuriki treasure comes, things will be a bit different.
I am not judging people who used them, it's their right to do so, I am only trying to think of possible counters to them.