They are making 3 new Stargate movies. The first movie was an indy film sold to MGM that was not really what the creators wanted. It is not very well connected to any of the Startgate shows. For example RA in the movie is not a Goa'uld. While I personally like SGU I was one of the few. SGU did not have a large fan base. The creator hope that after the movies they can get a new series started. :)
Carry on the franchise not reboot it, which is what the new movies are planning to do, they are going to disregard the what happened in the 3 TV series completely.
They should make a conclusion to SGU similar to the Final of Atlantis where they got the city back to Earth. (a movie not a new series)
Continue Stargate Atlantis and SG1 set a few years down the track from when the show's ended change a few cast members, because you can't expect them all to come back for more than a cameo role, most have moved on.
By the point the series ended they could even go the Star Trek route, Earth had ships capable of traveling to other galaxies , they were no longer limited by the Stargate for Space exploration.
SGU is one of my all time favorite shows and to make new movies when the show could still come back is well lame. I don't know where they plan on taking the movies but the first movie wasn't anything special to me. I'm sure it will look great but most action scifi movies have been lacking in the plot department with a few exceptions.