Ya i have noticed that not as many big fish pulls have been appearing. I have zero proof on this and am just basing this on "what it looks like" BUT, there seems to be a sweet spot for Gathering and Perception that has given me better odds. But with no way to clearly test this its purely speculation and what i see.
I have the Supra and all i70 gear, and if i use Spinach i get 383G and 306P and i seem to have less big pulls. But if i just use Rabbit Pie for example, I end up with 365G and 300P and i seem to have better success in getting more Big Fish pulls. Not all successful reels mind you but at least they come up more often.

Just my 2 cents