Really, if it weren't for the flash-forward's, there would be no reason to not give the episode a 10. I love the idea that this season will be taking Ollie back to events of his past, or perhaps more vaguely, characters (and actors) we haven't seen in years. How incredible was it to see Moira and Malcom back on screen (together!) for the first time since the season 5 crossover (and really season 2)? The show has missed those two mightily, but I also admire the guts of the writers at the time to kill them off when they did. Something The Flash almost certainly will never do with its 'beloved' characters.
Did I just write two paragraphs without even mentioning the Bruce Wayne/Batman mask easter eggs? Yeah, well those mentions don't really have the weight or impact they once did. Even so, hearing Prometheus say he's gotten advice from Wayne before certainly gave me chills.
One of the things I loved about the structure of the episode was that it didn't feel the need to explain everything to its audience. The Flash often struggles to understand how to communicate complicated plot to its viewers. Sometimes the answer is to just wing it and choose not to. We didn't even know what earth Ollie was on (or why) for quite a few scenes. That's much better than what CW typically attempts to do.
Couple of other things I need to mention: the Ollie/Dig scene in the car brought back memories and a massive smile to my face. The mansion made its return! Ollie repeating the "I'm 10 steps ahead of you" line to Chase was picture perfect. The Tommy/Oliver dynamic mirroring season 1 was awesome, even though most may consider it pandering. Whether or not next week's (and the rest of the season's episodes) live up to this week's is to be determined, but I'm just glad the show is about Ollie again. Because it definitely wasn't for the last 2 years.