I think the two most foul things about it are 1) expecting individuals to pay the difference to upgrade for the entire duration of the subscription all at once with no option to upgrade for shorter intervals and keeping the base subscription for whatever time isn’t upgraded, and 2) making individuals pay extra if they got the subscription using a discount.
#1 I think is easily addressed by giving people the option of upgrading to a higher tier by paying for a select amount of time and not forcing them to pay for it all at once. #2 is a little more low down, and Sony would be probably better off setting up a fixed fee for all essential players to upgrade instead of charging one person $60 and another $90 because one took advantage of a previous discount.
On a side note, it was never my understanding that PS Plus subs would be upgraded to higher tiers automatically, so i assumed anyone having only essential would pay an upgrade fee of some kind if they wanted access to the higher tiers. I’m assuming these complaints are different than people who bought up years of PS Now to take advantage of a loophole to get ps premium at a cheaper price because we were told it would convert to the highest tier.
Either way, people should speak with their wallets if they want anything to change and Sony to fix to it. The last thing Sony should want is for tons of bad press or for the service to be DOA.