Gonna use squid as my reference.
New tar:
Bad:
Can't hold down tar due to excessive self damage.
Can't manouver due to having to let go of tar and also wait for repairs.
Can't tar someone with any speed(due to the above).
Can't use it as cover to run away without loosing tons of speed and making your engines weaker to incoming fire.
Tar clouds appear slower, making it harder to know where exactly it is, if the enemy is in it or not, and when it activated.
Neutral: Apparently it doesn't move with the wind I've heard? Personally, I used that to my advantage a lot but others may like this better.
Good:
It does more damage which it didn't need since previous tar killed everything anyway.
I've been thinking a while and can't find anything else to put under the 'good' catagory. Remember, tar was barely a thing before and many people knew there was no downside. Why would this make anyone want to touch it now?