A single lancer, for sure is easy to kill. You just have to be careful with your horse, and keep it alive. Then, a cool block, and you throw yourself on him to slash his face with your sword, he just can't escape.
If you're a cuirassier, then, act like it ! Tank as much as possible, and get your giant sword into the ennemy.
If you're on foot, block and wait for some help
But if a cav (hussars for example) regiment face a lancer regiment, which is organized etc, there's way more challenge, and I personnally find this attractive. I'm a cavalry man for 2 years now, and I don't think lancers ruin the game, that's just another way to fight, and it's always good to know how to face a lancer or many.
Anyway, the last time the 7e faced a entire lancer regiment was on MMRussia, against the FK if I'm not mistaken. So yeah, doesn't really matter