In part, depends on the body of water. If you are fishing Metro lakes, 4lb is a real nice all around line. If chasing some walleye in big lakes like LOW or Winnipeg, better to have a stronger setup for that particular trip. Considering the largest Metro Eye I have ever caught was a tad over 6lbs, I’d think you are good to go! Caught plenty of gills and crappies on 4lb.
A way to mitigate the heavy line for smaller fish might be to run a few feet of lighter florocarbon line as a leader. This way you can adjust the leader line diameter to the size of fish you are targeting a little more effectively.