What is amazing about that I AM AN AVENGER cover is that both Firestar and Justice are in their George Perez costumes, and neither have worn those in years. Heck, both of them are in ongoing titles right now - Firestar in YOUNG ALLIES and Justice in AVENGERS ACADEMY - and neither are wearing those outfits. Is it just one of those "creative license" covers, or more?
The New Warriors, ideally, would have been Marvel's more modern stab at a Teen Titans franchise. When they debuted in 1990, they took several younger characters who'd floated around the books for years, and attached them a newer one, and had them be a team. Namorita was Namor's cousin and sidekick. Justice, then known as Marvel Boy, had a future self in Major Victory from GUARDIANS OF THE GALAXY and had hung around the Thing for a bit. Speedball was a creation of Steve Ditko coming off his own series. And Nova, or "Kid Nova" was coming off guest-starring in the FF for a bit. Their first volume ran for 75 issues, which is a very long run.
Why has the franchise struggled since? My argument is they've never been relaunched properly to cater to their strengths. About 1-2 years after the first volume ended, Marvel launched a second, around 1999 or so. The problem was the characters who returned got some horrendous costume designs - so poor that a few issues in, the editor on the letters page had to practically BEG that no more letters about how bad the outfits were would be printed or considered. It also took about 8 issues for a regular artist to stick around - and the series only lasted 11 issues (with an issue zero). It was one of the first major writing assignments from Jay Faerber, and let's say his best stuff came after.
After the 21st century, Marvel has basically become convinced the Warriors cannot sell, while never trying to sell them as the New Warriors. Zeb Wells & Scottie Young did a NEW WARRIORS mini series, but aside for the fact that it starred Nova, Night-Thrasher, Speedball, and Namorita, it had nothing to do with the NW as a franchise. It was a series about reality TV superheroes trying to fight crime and stick around on network TV. It was riding the Reality TV craze of the time, a craze that was better captured in comic form by Image's WILDGUARD. Young's artwork was awkward (at best), and it wasn't a success. Of course, CIVIL WAR gave the team a lot of exposure - and proceeded to kill half of the founders while branding them as the laughing stock of the Marvel Universe. Speedball would end up surviving, but would become so twisted as Penance that his entire character was destroyed, and even a great writer like Christos Gage is apparently forced to do a "slow road to recovery" to redeem him rather than a sharp 180. The only New Warriors characters who have flourished have been the ones who have remained apart in their own areas, like Nova in space and Justice in side Avengers material, and recently Firestar in...anything else.
When Marvel did finally decide to give the NW another ongoing series, they chose instead to again not make it about the actual team and the characters people loved. For a while, it was hard to figure out WHAT it was about, as it took many issues to even fully introduce the cast. It was a series about several depowered former X-Men being offered hi-tech costumes and training in order to be a new superhero team, which happened to take on the name New Warriors. The only connection was that Night Thrasher's brother Bandit had taken over the mantle and was basically using the team in a mad gambit to try to resurrect his brother. It was a task that failed, and left at least two of the new team dead, and the rest discouraged. The most noteworthy character on the book, Jubilee, has now returned to the X-office and her time as a New Warrior may as well have been one of Dan Slott's alternate reality tourists from SHE-HULK. Much like with Speedball, it took Christos Gage on AVENGERS: THE INITIATIVE to try to fix this dilemma, by having the new Thrasher basically re-assemble what was left of the "Old Warriors" and hang around Justice on the outskirts of the book for a while, fighting to uncover the Initiative's corruption (especially when Osborn took it over). Issues that didn't star Taskmaster were basically New Warriors issues in all but name, as it had so many NW characters in it, such as Justice, Rage, Ultra-Girl, Slapstick, and even Debrii (a newer character from the reality TV series).
Marvel does this with a lot of second and third tier franchises - insists that no one likes them and they don't have enough fans to support a title, yet when a relaunch is attempted, rather than cater it to the strengths of the franchise to specifically cater to what fans used to love, often those relaunches are used to promote some wonky new idea, and an old franchise's name is just stuck on due to fear of doing something new. Namor's had a few of those bizarre relaunches that little to do with what makes a Namor book work, and Dr. Strange has been a close second. For every IMMORTAL IRON FIST, Marvel has about two or three botched relaunches. It's like when Michael Jordon decided to play baseball - you don't cater to your strength, and quality suffers.
The last major development in the Firestar & Justice saga was in another anthology one shot - I HEART MARVEL: MASKED INTENTIONS, from 2006 just months before Civil War, when the two called off their engagement. Now Justice's rebounded with Ultra-Girl while Firestar's gotten and beaten cancer, and ran around ripping off SEX AND THE CITY with her gal-pals Pulsar, Black Cat, and Hellcat. While Justice has been part of the Avengers staff for a while, Firestar is part of the informal Young Allies.
Dan Abnett & Andy Lanning are likely writing the Nova story in that anthology, and I'd imagine Sean McKeever, who writes YOUNG ALLIES as well as the last FIRESTAR one shot that came out, will pen the Firestar/Justice story. As to what the future holds for the New Warriors, it's up in the air.