If you haven't decided on a basic game plan before you get inside of 1k on a particular plane then you might wanna rethink your game play. If I see a 190 or 109 I will give them the respect they deserve. I'll immediately assume the worst case scenario. They have may have more fire power, they may be able to outturn me, and they may have better energy capabilities. It's not until the first pass that I'll determine what exactly they may or may not be capable of as a plane and as a pilot. So basically my attacks will always be the same.
People already picked out the easier of the fights without this new icon system. Using an example like whether your going to attack a Spit V vs FM2 vs P-40B makes no difference. Everyone chooses their fights differently whether it be based on a general plane (Spit, 109, 190, or F4U), altitude advantage, energy advantage, or biggest threat in the area based on all of the above. You wouldn't attack the Spit V first if you knew a 109 or 190 of any variant was in the area. Simply because you would know that if you get tied up with the Spit V your setting yourself up for failure unless you can get the kill quick which isn't a guarantee.
The rules of engagement don't change much unless you fly wrecklessly in the first place. You should always respect the plane and the pilot your flying against. Just because they are in a early war or late war plane doesn't mean you'll win the fight. It takes the pilot and the aircraft to win a fight not just the aircraft. There is no such thing as an uber aircraft that will win every engagement for you. The pilot behind the aircraft is what makes a difference and with as many people as we play against you'll never know the outcome based purely on early war or late war rides.