GnR are very popular, I have little doubt tickets will be expensive and they will sell. I don't have an issue with it, they just aren't a band I want to spend money on compared to Motley who may have a worse performance but for me, I've never seen and always liked (plus add the other bands and its a win for me). If GNR announced some other awesome bands that were opening, I'd consider it, but it doesn't seem like it and maybe they don't need the support.
For my classic hard rock concerts this summer, it's actually looking really awesome, but leaves little options for good support for GnR:
June 19th - Alice Cooper, Tesla, and Lita Ford @ PNC Bank Arts Center, Holmdel NJ
June 22nd - Ozzy and Marilyn Manson @ Madison Square Garden, New York City NY
August 4th - Journey and The Pretenders @ PNC Bank Arts Center, Holmdel NJ
August 15th - Motley Crue, Def Leppard, Poison, Joan Jett @ Citizens Bank Park, Philadelphia PA
August 20th - Foreigner, Kansas, & Europe @ PNC Bank Arts Center, Holmdel NJ
August 21st - Sammy Hagar & The Circle, Whitesnake, and Night Ranger @ PNC Bank Arts Center, Holmdel NJ
September 18th - Aerosmith and Extreme @ Fenway Park, Boston MA