Revisiting this civ after quite a long break from Civilization, I've had plenty of fun with a refreshed perspective of Meiji in VP. Here's my take on the uniques:
Unique Ability
Very powerful in the late game, capable of pulling a strong policy lead comparable to Brazil's, with the extra culture on cultural buildings providing decent options for the early game. The UA strongly directs Meiji towards Tradition-Artistry-Freedom, with three notable benefits:
- The early culture on monuments allows a solid opening with Monument-Stonehenge, as you get an edge over most civs trying to do the same for getting Tradition's +2
pop opener 3 or 4 turns earlier than usual.
- The bonus towards production and reduced military costs greatly mitigate Tradition's infrastructure issues once your golden ages start going, letting Tradition Meiji build its cities in the post-Renaissance game (or earlier, if Notre Dame is secured) as well as Progress.
- The reduced military cost works extremely well with both Draft Registration and Arsenal of Democracy, and at a time when Mikasa is active for GAP generation and naval dominance.
As a note, the presence of Baths as one of the cultural buildings, as well as this building's effect during golden ages, push Meiji to give particular attention to fresh water locations. If Meiji doesn't have a starting bias, a river or lake bias would be a solid option for this civ.
Sohei and Mikasa
Great UUs for their economic aspects. Sohei acts as a free Zealotry or Draft Registration during Medieval and Renaissance, a time when your production is pressed by the many important wonders of these two eras. Moreover, the faith from kills can help spreading your religion when the race for conversion and reformation is at its peak. Meanwhile, Mikasa comes about the time when a Tradition-Artistry path is about to chain golden ages, helping you sustain them in case you weren't able to get Notre Dame, Chichen Itza or Taj Mahal, and well timed for the UA's 20% cost reduction.
Mikasa's free Targeting I promotion proved valuable for the access to tier 4 promotions as soon as they are built. Added to the Nippon Kaigun's combat bonuses, Meiji has a solid fleet to protect its cargo ships by the time the Zaibatsu comes online, even with a relatively small fleet.
Zaibatsu
Having two franchise scalers is indeed very powerful, until you draw everyone's attention and they propose to sanction you. The latter practically kills this UB, as sanctions are a very popular proposal among the AI and Meiji doesn't have the extra delegates that Austria or Germany do to fight all AIs bandwagon on sanctioning you.
The free stock exchange from the opening Zaibatsu national wonder is in the same tech column that the Empire State Building comes at, pushing the player to build these two in different cities. The extra merchant specialist may be wasted when doing that, as satellite cities do not tend to use merchant specialists, even with Freedom's Civil Society, for lacking Tradition's reduced food consumption in the Capital. However, wasting the merchant slot is rather inconsequential due to other specialist types having higher priority at this point and could be replaced to something more relevant to this civ.
Overall, the Zaibatsu is strong in theory, but unreliable as a unique. It is very easy to shut down for how late it comes to action, and the AI is bound to do so before you can spread your franchises anywhere close to your franchise limit. I think it needs some sort of safeguard for when the AI chooses you as the next target of their many sanction proposals, like having the national wonder count as a few franchises.
As a bug report, the offices didn't receive Transnationalism's +2

culture. Maybe it is a bug on the tenet itself, but I'm leaving here in case the unique corporations are not flagged properly for the tier 2 corporation tenets. Another thing is that the civ is referred as only "Japan", just like with Nobunaga. If both Meiji and Nobunaga are in play, a "Sanction: Japan" proposal from any AI causes confusion, with no good way to tell which one is being targeted and you being unable to ignore it due to your Zaibatsu UB.
Imperial Shrine
Powerful building on its own, but one that is hard to fit in the cities's production queue when it comes online. Being unlocked at Theology, while great due to the tech's high priority, also means that the Capital will likely be busy competing for Hagia Sophia and Borobudur. Meanwhile, the satellite cities will likely be struggling to keep up with the Classical Era infrastructure. Given that the Classical Era infrastructure includes the Amphitheater and the Bath, which receive the +1


culture/GAP from the UA, the Imperial Shrine can be neglected for quite some time, as it isn't as cost effective for its yields as the classical buildings available to Meiji.
I think the Imperial Shrine could replace a classical building instead, notably the Bath, for both historical and mechanical reasons. Historically, one of the oldest imperial shrines in Japan, Kashima Shrine, is recorded to have been built around 600 BC and said to have been founded by the first emperor himself, dedicated to a patron deity of martial arts, which befits the extra supply and promotion of the UB. The Classical Era also represents a period in which the Japanese emperors held actual administrative power, while the Medieval Era represents a period in which this power was held by a shogun instead; moving this unique away from Medieval would help distinguish Meiji's theme from Nobunaga's.
Mechanically, the Bath's effect is more in line than the Circus to what the UA is trying to achieve, and an unique bath could remove the dependency on fresh water for this civ's consistency. Between the +1


culture/GAP from the UA, the culture modifier during GAs and Tradition's Splendor giving another +2

culture to baths, this civ can see some notable difference in performance solely based on whether it started near fresh water or not.