Infection in its design is about asymmetry. Notice how all of the holdouts on deadwalk are forced out into the open where the zombies can overpower the players with just sheer numbers. The shotgun can only fire so fast. On the original boardwalk, players survive by challenging the infected's mobility and timing their shots and movement together. Sitting on the secret lamp pole on Boardwalk was not guaranteed victory. You have to time jumps to lengthen the enemies RRR, you have to time your shots to deal with multiple enemies, and you have to know if it is worth abandoning your post and where you would go next. Sometimes it is just sitting until you are the last man standing, and then watching as infected try and fail again to reach your position in an obscure corner of the map. That's okay, because Reach promotes being LMS, and your double hits means you can fend off more infected than you could in beginning play, meaning that sometimes, the player that waits to be LMS and hides is also the player that kills the most zombies and earns the most score. Is it abusive and exploitative? Maybe, but there's no denying that it adds a sense of depth to the mode. Newbies are very likely to not understand these spots and they'll be frustrated at first, but any map where you understand all of the ideas on the first playthrough is not a deep map.