Drop rates weren't changed. Like I've told @EB1972 before, it's just RNG. I've gotten plenty of 5* gear myself from grinding Campaign during the Sir Nick tourney. 

It's going worse now, after the last update. Ony get 3 stars gear,
ridiculous.
I have the feeling that everything keeps getting worse.

Feels the same, sometimes that's just RNG

it would be really nice and take the frustration out out of farming if there was information on %drop chance for gear.

geeze this would aleveaite so much pain and so simple why it hasent be done allready is beyond me... or maybe it has and I don't know where. 

Yes Campaign I get junk gear to. pffff

then they are allowed to adjust the script, which can drop better gear in very difficult levels such as nightmair 

Dragon lair there i get 5 stars gears, thats better.

if you are talking about campaign then it does not surprise me, I get junk gear from campaign

I personally have better luck in the dungeons for gear drops