Netsu meter management
"Meter management? What meter management? There's no meter in Tekken!"
That was the case prior to TTT2 and although netsu existed in TTT, there were no ways to use it for anything other than increasing hit/combo damage. Now in TTT2, a new gameplay mechanic has been introduced that allows to use your netsu meter defensively to safely tag in your partner. "Tag Crash" can only be performed when your point character is grounded and it allows your secondary character to do a jumping roll into the arena interrupting your opponent's pressure. It deals no damage, but is safe to retaliation and stops any strings being used. Since it does require your netsu meter to activate, it should only be used when your point character is low on health (and close to being knocked out) or is lower on health and is by a wall which could lead to a KO (I talked about this in Dragunov Pt. 1).
In TTT, netsu was activated as your point character took a specific amount of damage. Team composition was important as certain characters would activate netsu earlier (i.e. Jin and Jun) while other team compositions might possibly not activate netsu at all (i.e. Mishima teams). Otherwise the amount of hits necessary was a set 5 hits with only a few characters having required less or more to activate (you can read the specifics here).
Now in TTT2, it's as simple as either a character enrages easily (40% damage taken) or not (70% damage taken). No longer are teams limited to certain, predisposed compositions to be competitive. The only major benefit to having related partners (whether by blood, friendship, or enemies) is that team specific throws and combos still exist that destroy the opponent's red health. This generally look more bad ass and do more damage as they are often performed off of command throws that naturally do more damage than a generic, in this case 2+5, throw.
New to TTT2 is also the "Tag Assault" system which also has the major drawback, and in some rare cases I will mention benefit, of activating your opponent's netsu meter regardless of the amount of damage the combo dealt. That means as soon as the combo is finished the opponent can Tag Crash in an interrupt any future oki/pressure. This also means if you do not apply proper pressure the opponent can hard tag out and bring in a character (such as Dragunov, Paul, or Jaycee) that can deal massive damage while enraged.
Netsu is similar to BR rage as it allows your character to deal 30% more damage on all their attacks. This also naturally favors standing strings as NCc standing strings do not decay on combo damage and often have "clean" damage attributes to further increase their damage. As such it's in your best interest to not fight an enraged character as one random event can drastically change the outcome of the round.
Using what we learned from the prior section, if we can start a combo (if even a small juggle) on a point character who's currently enraged and perform a TA on them, their secondary character will then automatically activate netsu. Since two characters, on the same team, cannot be simultaneously enraged it will deactivate the netsu on the point character. This will force the opponent to tag in the, presumably, more damaged character later in the match. As such this is a hard counter to characters that are exponentially more dangerous with netsu activated.
Pros & Cons of TA/TC:
While not immediately visible, there are major drawbacks to both Tag Assault and Tag Crash. Most notably in either case you must use your netsu meter while performing either. Luckily if your secondary character is full life and has no netsu, the only negative effect is activating your opponent's netsu, but the same can't be said for Tag Crash.
Increases the damage potential of combos for all characters
Reduces the deficiencies of your point character when using the proper TA assists
Automatically activates your opponent's netsu
Uses the netsu of your point character (if available)
Uses the netsu of your secondary character (if available)
Destroys the red life of your secondary character (if available)
Allows you to more safely tag out your point character
With your back to the wall, it often causes side change
Despite being a safe option, your point character can still be hit and knocked out while tag crashing
Uses the netsu of your secondary character (must be available)
Destroys the red life of your point character