I spoke to the people at Diamond and they confirmed that they are only making "Pro-Cut" pockets now, and are no longer making tables with "League-Cut" pockets as a regular thing. Many Diamonds are essentially custom-made, however, or made-to-order, and they will cut the pockets however you want them.
I play on nine-year-old 9-footers with League-Cut pockets at a pool room and really like them, and this past week found a bowling alley that has 11 Diamond 7-footers, two of which have the Pro-Cut pockets. So I played a number of practice tables on both the League-Cut and Pro-Cut 7-footers just to get a feel for the difference. They really didn't play all that much differently for me, although my home table has very tight pockets (my nickname for my own table is "Rattle and Hang"). The League-Cut pockets did seem more accepting.
The real difference to me was this: about five times while clearing five tables on the League-Cut pockets, balls went in that I didn't think should have gone in--the aim was just a bit too far off, and I was surprised the balls fell anyway. And, on the tables with the Pro-Cut pockets, there were at least two times where balls rattled and I thought it was a cheat--that is, I felt that I had hit the ball true enough that it should have dropped, but it jawed instead.
In both cases what I used to evaluate this was simply my "feeling of surprise." Surprise that the ball did drop when I thought it wasn't going to, and surprise that it didn't drop when I felt that it should.
Your mileage may vary of course.