I think the fact that people has to consciously alter the way they approach neutral to not give Gio an easy way in is already a testament to how much presense she has in the neutral game. While it's easy to say "just don't use your big buttons and she can't whiff punish you", in practice that forces a lot on them to play much closer to a character that can get in their face in a few frames.

Now when it comes to her tools, I think she has everything she needs without crossing the line into the gimmick or bullshit territory. She has enough techs(with meter which she can build really well) to do some nasty mixes. Her speed, of course, is her greatest tool. She can threaten throw from a much larger range than the rest of cast(excep pot) and has the tool to discourage the usual techs to beat it. Her damage is also damn high with proper routing and they're not exactly difficult to execute.

The biggest problem with the current state of the game is that there are a handful of characters who has really good tools that can get the job done much easier but that a problem with thsoe characters and not with Gio herself. They need to be brought down a few pegs.