By Hector Saldaña - Express-NewsThe show: The Goo Goo Dolls made its San Antonio Stock Show & Rodeo debut on FridayAttendance: About 16,000 people (sold out)First take: Singer-guitarist John Rzeznik, bassist Robby Takac and drummer Mike Malinin energetically led this expanded band, opening with the soaring “I’ll Stay With You,” a song that managed to somehow embrace the most epic, crashing rock and reinvent the power ballad at the same time. Goo Goo Dolls virtually perfected this genre — loud-quiet, emotional, slightly lovelorn Dylan-ish and post-grunge. Rzeznik had barely touched his acoust