Ya, and they are over-used to a point. They are some of my favorite villains period as well, but even Voyager really started to stretch their "coolness" by overuse. I remember when they first appeared they were so mysterious, and scary because of the unknown factor.
Ya you could make a million ways (to me would feel forced) to bring the Borg out of the Delta Quadrant and into the Beta/Alpha Quadrant. You could do worm holes, you could have some experimental warp drive, you could go into the history of Guinan's people who are the survivors of the Borg invasion then they escaped and spread throughout the galaxy. Where as Guinan first came to Earth in the 19th century (one of my favorite two parters in TNG) Ya you could find ways to do it, but I just don't want more over use of the characters as of yet. And to me the Borg best fit the TNG era more so then Kirk's.
It would be a stretch and somewhat of a long winded subplot to bring the Borg into the Federation space in a film. You could not just go, boom they were here because time and stuff. The reason they made ST09 the way they did was not to anger the fans. To allow both universes to exist at the same time, and not alter too much, and they had to do that with great detail. So bringing the Borg around would be too much of a chore and unneeded.
Some day I want to see the Borg return but not now. Hopefully in a new TV series sometime in the future.