90% of people reading this post know exactly what I'm talking about and don't need to see this. This is for the remaining 10%–especially the new players!
Lakeville and Overlord are the two maps with by far the worst "bad flanks": the valley on Lakeville and the beach on Overlord. They're both on the west side. The beach is inviting because you get to go fast moving downhill toward it, and the valley is inviting because it looks nice and uncomplicated. In 99% of matches, you must resist this because going there is a BAD IDEA. Here's why.
Lakeville valley is very soft terrain and narrows down to a single elevated choke point. This means that attacking through it is dangerous and slow, and defending it is easy. Even if you win the flank, you're going to 1) take an unreasonable amount of damage doing it, HP that would have been better spent in the city fight and 2) take forever actually getting out of there to capitalize on it, time the rest of your team will have to deal with being outnumbered in the city. The team who loses the flank has lots of time to realize that fact and deploy vehicles to shoot you to pieces as you attempt to get into the exposed cap circle. As a result of all these, any team that sends the majority of its short-range units into the valley is *almost certain* to lose. Can valley pushes work? Once in a while, usually when their comrades pull an upset victory against superior opponents in the city–which means the match was won *in spite of* a valley push rather than because of it. Should you always avoid the valley? No, you do need one or two vehicles to defend it, but never more than that.
Overlord beach isn't AS bad as Lakeville valley, but it's still bad and for similar reasons. It's fun driving downhill onto it, but you'll have to drive uphill the same distance to get OUT of it. Just like Lakeville valley, this takes a long time and the enemy has plenty of time to get ready for you. Being on low ground means that opposing vehicles can shoot down through your thin top armor at unpredictable times. And once you do get up the bluffs, you have to cross open ground to get to hard cover. All of this means you lose great chunks of HP uselessly. Assuming you manage all that, the only way it actually gets your team the tactical advantage is if their tanks are still on the reverse slope of the middle hills–very unlikely given how much warning they got. Can beach pushes work? Maybe?…I can't actually think of an example. Should you always avoid the beach? I know I do, and my teams generally react quickly to heavies coming up from an undefended beach.
TL;DR Valley is too defendey and slow. Beach is too low. Neither are useful. Don't go to either.
