Seconding this, if you dropped OpenTTD because of the simplistic passenger/cargo routing (i.e. take any cargo to any place and pay is only based on how far you took it) then definitely give the CargoDist option a try.

Every passenger (or mail or manufactured good) has a unique destination in your system that you need to get it to. They are roughly balanced based on demand (two stations in large cities will generate a lot of traffic between them, but a small town will only generate a small amount of traffic to and from a large city). It makes the transport routing game way more interesting and more like the routing of passengers in more traditional Sim City type games.

Beyond just that, the ability for passengers to "route" themselves (Take airplane from CityA -> CityB, then rail from CityB -> CityC, then bus from CityC to CityD... and back) is the bigger, more important effect of the CargoDist feature.

That means you can form "Hub and Spokes" for passenger traffic, and the individual passengers are smart enough to figure out how to route themselves to their ultimate destinations.

------------

Its the most "realistic feeling" traffic mod I've found of any of these games, honestly. Even Cities Skylines seems rather basic in comparison.

-----------

I play on Passengers/Mail as CargoDist, and then all other traffic (Coal, Wood, Cargo, Oil, etc. etc.) as default / original rules.

I also set the "symmetry" of CargoDist to 80%. That is, 20% of traffic is one-way, which seems to be correct in my opinion? I think it defaults to 100%, but it doesn't make sense for _ALL_ traffic to be bidirectional (ie: for all agents to make a return trip each time).

EDIT: I do think that a "big mod" to OpenTTD under a new name would be beneficial to the project. Something that redefines OpenTTD's sizes (each square is supposed to be a square km, but it doesn't "feel" like it. Roads aren't a square km wide after all...). I think that if each square were 10m x 10m nominal, and then for all other parts of the game to be redesigned off of that (scaling up docks, rail depos, cities, etc. etc. as appropriate to this new size), would be really all that OpenTTD needs. Plus CargoDist Passengers/Mail by default.