Yes, it is a big deal!
For the past three years we have cherry picked our champs we rank based on the interaction of MD/Dexterity ....
Both trouble some defenders and offensive champs to counter those defenders. Some champs we didnt rank because of their ability buffs and how it fueled MD. Now those champs would be a lot more useful with the changes and some mystic defenders may not be as much trouble. Again, Three years we've been accustom to this game play and it was a HUGE FACTOR on who we chose to rank. Something definitely needs to be figured out on how get the players on their best foot forward with these changes.