Customs is an absolutely brutal map for beginners, especially in it's current state, and sherpa-ing two Noobs I truly realized the extent of just how awful the map is unless you know every facet of its… quirks.
Lack of mobility- Customs is essentially three lanes: factory/construction area, Wooded area, and the main road. Each presents their own terrain, but transitioning between each lane is really restrictive and confusing until you know it. Two holes in a wall that are about a kilometer apart? You can jump from the railway on one part of the factory area to reach another segment, but there's no way to easily return, etc, etc.
Whack-a-mole- Customs probably has the most unforgiving landscape out of any map minus factory. There is so much barren, exposed area where you get preyed upon. Crossing the land bridges under big red so you can actually get to the rest of the map? Have fun getting your back shredded by someone sitting on the hill behind you where they have plenty of concealment and cover! Trying to get to your extract through gas station, hope you enjoy being sniped by the mosin man that's always sitting on that rock face! Make sure not to cross the open areas that are covered by machine guns if another player or god forbid reshala is waiting for you! Dont know the 5 or so scav sniper spawns? Adios! The Dorms area ironically has the best concealment and movement options outside the actual factory buildings, but of course that's where the chads go. It's way more unforgiving then an open map like shoreline where you can hit the deck or hide by some rocks, or reserve where you have multiple buildings to weave through.
The part everyone already knows about. I firmly believe that big red spawns are the worst in the game, bar none, especially after the woods changes. It is honestly unbelievable just how astoundingly terrible the big red spawns are. I feel like a fucking big 10 college football coach drawing up a play trying to show my friends how not to die in 10 seconds on this side of the map, after they wait 10 minutes to even get in a game, and still they're probably going to get annihilated by some guy anyways. I legitimately can more easily avoid combat in factory then this side of the map.
Customs is an enjoyable map, I love it despite its flaws (though the big red spawns almost ruin it) but the reason they shoehorn beginners here is lost on me. I honestly think it's one of the most unforgiving maps in the game. They either need to expand it to solve its woes or heavily rework quest order, in my opinion. I feel like many people get turned off on the game after feeling like they have to run exclusively customs.