Regarding the blower, if it is turning easy this is a good thing a long as the bearing has no side to side movement.
Your unit running all the time in hot weather is not a bad thing as it has removed humidity and brought your temperature down somewhat. You need to remove humidity or you will be cooler and damp as well and that may make you uncomfortable.
Of course one would need to compare your rate of cooling to other years to know if there the condition that is happing today is a problem or normal.
As for some rooms in your house colder then others this can be easily fixed by checking all the vents in your house to make sure they are open or are some closed. If you are forcing all the air to one room then you will have one room colder then others. Open vents in the other rooms to allow more cooling in those rooms. This may be why you are having trouble cooling down your house. You are not getting proper flow from all the vents. If all the vents are open then one of the duct dampers may need opening or closing. The dampers would be in the basement if that is where your furnace is.
Not sure how old your units are but if you feel they are that old that they need replacing and the 600 per year is worth while then change them. I would make the repairs bearing and adjust the vents first though. It will most likely make a difference to your comfort.