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About the map: I like the vegetation, but I do not like the overall map design. Once more it is full of artificial terraces. Terraces do not reflect a naturally emerged landscape, but are usually human made. There might be a couple of spots on earth where terraces have grown naturally, but that is rare. Now, if you cover terraces with jungle, it looks like a sunken feral landscape of a vanished civilization. Sadly there appear no traces of a vanished civilisation on the map. Accordingly the map appears crude and the creation process ill-advised. This makes it another artificially appearing battle arena, like we know them from so many games.
I could also argue that you won't see any remains of a vanished civilization after a couple of hundred years, especially with all that vegetation eating away at the structures. Who knows how long those terraces have been abandoned. On the other hand, I haven't really played it long enough and at the moment it does feel kind of rough.
In BattleTech, the first manned interstellar expedition (with the help of Kearny-Fuchida jump drive) takes place in 2108, and mass colonization of habitable systems follows thereafter. Sporadic fighting between emerging planetary empires takes place but only turns into galaxy-wide conflict 2398 (beginning the so-called Age of War), which only ends with the formation of Star League in 2566 (with the Reunification War lasting up to 2596); the Star League collapses in 2766 (the start of the bloody Amaris Civil War), and this was insta-followed by the four Succession Wars that almost wiped out civilization in the Inner Sphere and left entire systems barren (what with radical elements within ComStar hastening the collapse), lasting until 3030. Operation REVIVAL (Clan invasion) started in 3049.
So, the civilization on the planet may have collapsed almost a thousand years back - although most likely time periods would be either Age of War (500-650 years ago) or from the collapse of Star League until the end of First Succession War (200-300 years ago) - in both times ABC weapons, kinetic strikes, and the like were used quite liberally.
I'd say the map is at the very least "plausible". Buildings would start to collapse within decades (depending on the climate); solid concrete will last for thousands of years but would be fully overgrown in a couple of centuries. The town of Pripyat is a good real-life example - not even 30 years after the evacuation, buildings there have already started to collapse.
For more information, see the documentary
Aftermath: Population Zero or similar documentary series
Life after People.