Like many people I had nostalgia for old early/mid 2000s G4, but unfortunately I actually rewatched some of these shows recently on youtube and ummm, they kinda suck. I know there weren't a ton of sources of video reviews of games at that point since this was pre-youtube, but their reviews and video game content has mostly aged poorly. Especially X-Play which might have the worst video game reviews I've ever seen. I really wish I'd kept old G4 in the past since rewatching it kinda lowered my opinion of it.
But as far as new content goes I think they'll be fighting an uphill battle. Sure, they'll bait several thousand peole based off the name alone, but they have way, way more competition these days when it comes to content. I don't see it working out.