This way you'll have a clear marker of progression, the two islands can be made different and diverse, the two cities would be clearly the anchors of their respective islands and mission locations could be made more interesting. The map proposed has plenty of wilderness areas as well as a number of other settlements which serve as secondary locations.
Crime
Kicking things off with Buenos Aires, we're off to a tough start. Not because there isn't much crime — there's plenty — it's just that official statistics are very rarely released, and when they are, the reports regarding the data vary giving us anything but a clear picture.
However, to get a rough idea of where we're at, the OSAC rates the crime situation in the city as "critical". Buenos Aires hasn't been able to escape the markers that are true for almost all major South American cities. Gang activity, violence, drug trade, weapons trafficking and more are ripe, even more so than in inland cities due to the active port.
Murder is most often related to gang affiliation, though non-gang related violent crimes are also pretty common, with rates estimated to be well about USA averages. Organised crime is a major issue in Buenos Aires.
Which leads us to another key criminal field: corruption. No matter how we twist things, South America has a reputation for being a hotbed of corruption, and unfortunately, that rep is well earned. Corruption is a major concern, as prominent politicians often are discovered of having ties to various syndicates. Much of Buenos Aires' taxis are also thought to be under the control of crime bosses, however, this has yet to be verified.
Montevideo is a slightly different story. The OSAC rates its crime situation as "high" instead of critical, and the general consensus is that foreigners will generally only experience petty crimes such as pickpocketing or burglary. However, the two major issues present in Buenos Aires are present here too — gangs and corruption.
Both of these issues in both cities are rarely something that is seen or it apparent to tourists or even foreigners who live there for a year or two, however they are present nonetheless. While both cities struggle against these crimes, the truth is that they both fit the GTA profile perfectly, so both Buenos Aires and Montevideo is scoring well in this regard.
Recognition
Yet another category in which both cities will shine. As the capitals of their nations and popular tourist destinations, both Buenos Aires and Montevideo will be relatively easy to identify based on landmarks alone even for foreigners who aren't completely sheltered.
Both cities are heavy on landmarks, and we couldn't possible hope to list them all. That said, a few highlights from Buenos Aires include the Palace of the Argentine National Congress, Palacio Barolo, Parque Centenario, Puerto Madero (the most modernised district), Puente de la Mujer, the Obelisco and the Casa Rosada.
Moving on to Montevideo, some major landmarks include Parque Prado, Parque Rodó, Obelisk of Montevideo, the Monumento La Carreta, the Palacio Salvo, the Plaza de la Constitución, World Trade Center Montevideo, the Legislative Palace and the port.
You might have noticed that not only are many of the landmarks between the two cities similar, but they both have an obelisk. Nonetheless, Rockstar would be able to differentiate the two cities visually by focusing on industrial elements in Buenos Aires and more modern elements in Montevideo.
Story Potential
We'll be damned if this pairing of cities doesn't have some serious story potential. It could play on the rivalries, the gangs, the corruption and more. It could incorporate elements of the massive recession that struck the region years ago, it could touch upon the 2018 olympics, and it could be framed around the activities of corrupt officials.
If we stick to the generalization — which, let us reiterate, isn't accurate and we don't wish to offend anyone — that Buenos Aires is somewhat poorer and more focused on industry, while Montevideo is richer, more modern and focuses on banking, we'd get an interesting dynamic. Buenos Aires would have more down-to-earth criminals like your standard gang-members and whatnot, while Montevideo would be full of the corrupt politicians and bankers.
The protagonist would start off in the wilderness are of the Buenos Aires island. Having arrived at a small coastal village by sea, the man with a criminal past was almost instantly mugged and beaten. A local small-time crime lord's men find him and take him to the boss. Based on his tattoos, the boss recognizes him as a member of the gang of a friend in another city, so he takes the protagonist in. Initially, missions would take place in the non-city area, with the city being eventually unlocked.
Once the city is unlocked, the protagonist is introduced to the larger narrative arc. For years, there was a deal between the gangs of Buenos Aires and the syndicates of Montevideo that worked to mutual benefit, however recently old rivalries have made the deal uneasy and it might collapse into gang warfare. Various gangs, corrupt officials, bankers, syndicates and crime bosses have countless needs, demands and interests, many of which are conflicting.
The player would get tangled in a web of debt and association, when paying off one debt means racking up three more. Eventually, through various missions for the different factions, tensions are seemingly being eased. However, it is revealed that an unknown party wants the deal to deteriorate, and uses the progress of the protagonist to simply push the Buenos Aires gangs and Montevideo syndicates further apart.
Suspecting that the unknown enemy operates out of Montevideo, the second island is unlocked. Doing missions there grants the protagonist more money, an easier life and many luxuries. His allies back with the gangs stop trusting him, because they think he's become like the bankers and corrupt officials, who in turn don't trust him because he's originally affiliated with the gangs.
Here, the plot would take on a theme revolving around deception, betrayal and blackmailing, as the protagonist navigates the strange world of the wealthy and the corrupt. As the story progresses, more and more former allies turn their backs on him as he gains more influence, more infamy and more wealth.
In a carefully choreographed revelation, the players are shown that there in fact is no "hidden enemy", but simply the gangs and syndicates are no longer capable of working together due to procedural changes in ideology, and that the acts of the protagonist were pushing them further away without his knowing.
Once everyone had turned their back on the player character, he realises that with the information he's collected throughout the game, he could either ignite a devastating gang-war and disappear, or coerce and blackmail everyone into a proverbial corner, turning him into the de-facto criminal kingpin of both cities. The player may choose which ending happens.
Final Verdict
A++
Pros: geography, crime, recognition, story potential, everything
Cons: Con? What's a "con"?
While they have the benefit of being in this together, the pairing of Buenos Aires and Montevideo has proven to be the single best candidate for the setting of the next major GTA game that we've looked at in this article series yet. They nail every aspect and then some. We have a winner. Cheers.
Would you like to play a GTA game set in these two cities?