Yes, sealing a driveway every year just because it keeps the jet black color can be bad for the driveway. Its like painting something too many times. It builds and builds, gets too thick and then the sealer cracks. Once this happens it's almost impossible to fix.
We recommend sealing your driveway every 2-5 years to protect it from weathering, cracking, and fading.
Crack Filling is a maintenance item not a repair of the crack. Cracks usually will still be lower than the surrounding asphalt. They also will appear darker, like a shadow, than the surrounding pavement. It is normal for the sealer to crack on top of the crack filler as the sealer does not expand and contract like crack filler does. Crack filler will also remain soft and flexible.