Yep, those 300-600k missions in the bubble were certainly nice to come across, and now they are not seen.
Like Ziggy said, there was a major exploit that was lots of fun and people were enjoying the smuggling experience and the millions of credits is was getting them. Smuggling got hit with a nerf all the way across the board, so now smuggling missions are rare to come across, and when you do find them in the bubble, they pay peanuts.
Bummer. I rather enjoyed smuggling in the bubble before 1.4 hit, as there were plenty of missions, an they paid me 100-300k, and I got to travel around and see some lots of systems. Not so much anymore. The exploit was rather interesting, and I admit I did three runs and had some fun. But the price being paid is that smuggling is a rare thing now and pays in belly-button lent.