No, not at all. (Although you should keep your sweepers with your vehicle)
Here's what you do. Go play a dozen games and plant mines like crazy. Then, when you're up against someone using mines. Think about where YOU WOULD PUT THEM.
Helps tremendously at not running over mines. Don't blindly run over roads or through gaps or take the quickest path into the strat point etc etc. Also lets you have a pretty good idea on where to send the mine sweepers.
Mine placement is not random. It's largely predictable with experience and in some cases common sense. (Angoville intersection for example) 1, maybe 2 mine sweepers (on larger maps) is plenty.
With vaulting, you can almost always avoid this stuff. The only mines that are kind of bullshit is putting them on the back side of a building by the door where he will never see them from the default camera angle and gibbing his squad when he enters/exits the building.
Yes sweepers are important, and yes you should be actively checking areas for mines frequently, but it is very hard to do in smaller game modes where units are frequently split up into single unit groups and you simply cannot micro that many men.
The AoE was lower before because of balance issues with wipes. Now that we had to increase AoE mines represent too large a threat, as you would expect. There needs to be a solution to deal with this problem that allows players a chance to respond to the threat without sweepers.
Mines, even when detected can be very effective, and a single munitions to munitions cost is not representative for this device. Mines are designed to force opponents to take opportunity cost losses, by slowing attacks, or forcing sweeps before attacks, or prelim arty, etc. Therefore, simply knowing a mine is present and removing it does not automatically mean equal sharing of costs. Even in real life mines rarely do large amounts of damage to armies, but they force decisions to be made which do cause serious and long lasting consequences.