Creator Backlash: Artist Brett Booth was very vocal about his displeasure with Wally's initial absence from the New 52. In an example of this working out for the best, when DC decided it was time to reintroduce Wally, they approached Booth about taking over art duties on the series.
When Titans and Young Justice was merged to create the 2003 Teen Titans revival, Bart was renamed "Kid Flash" and given a personality transplant, removing his ADD-driven, humor-based personality to turn him into a brooding teenager who kept wanting to be taken seriously. He's been acting more like his old self since his resurrection, though.
Previously, Wally's Crisis-era depowering fits with the general trend to bring top-level heroics down to less fantastic levels.
In the Rebirth collected edition, Geoff Johns' pitch for the 2010 Flash series is included, and features a more substantial role for Wally. However, as the pitch concludes by noting it would be leading into Flashpoint in 2011, it appears that much of this dropped due to the Schedule Slip the final issues of Rebirth suffered from.
Prior to Wally's New 52 reintroduction, Brett Booth posted several ideas for Wally's costume on his personal blog - Whilst mostly resembling the costume Wally had been wearing prior to the reboot, one major difference was the use of black on the hands & the waist down◊ to give Wally a costume that whilst resembling Barry's, would allow the reader to easily distinguish between the two Flashes at a glance; and an alternate color scheme on the same costume, replacing the red & gold other with blue & silver◊ - ultimately, Booth would use a different design when he got to reintroduce Wally to the DCU.