The more I think about this, the more I'm ok with Gareth coming back. He left when the club was in transition and he was frustrated by the club's inability to crack into Europe. He left with very little rancor, and has not disrespected Villa since.
If he's willing to accept a massive reduction in wages, then I'd welcome him back. But I think he'd want to stay on those wages, so I can see a club like Spurs or Arsenal bid for him. Maybe even PSG.