Yes they made it harder
Yes it is intentional
Yes it could be unfair (between player who passed it pre-2.0 and those who have to after 2.0)
No there is nothing wrong with a CHALLENGING fight being hard
No they won't fix it, because it is intentional.

The ONLY thing that I feel that they should have done but haven't is remove a star from all the fight that they boosted the difficulty for so everyone have to re-pass it, it's only fair (granted, they probably should "gate" it by power, I mean there is no point in doing this to a lv 85 45k power on a lv 30 instance, so it could get complicated. I'm kinda curious how many fights are modified thou, this is by far the most famous but I think there are a few more)

Would it kill you to search for this topic first? There are literally dozens of them....