Getting old with the GP disparity - every level is having this problem besides Kyber 1

Each to their own. I'm 'pretty' happy with GAC. Personally, I don't think sandbaggers would put too many players off of spending. If you think about it, the more you spend, the less sandbaggers you'll see.

My biggest concern about spending is that the support is useless. If I spend money and there's a problem, I'm not confident it'd be rectified.

As for proving grounds; you need some serious teams to beat them. Each event took a different team for me too. They're not even a formality for GLs.