Gold+Gold is certainly better than Platinum+Silver since STE+ matters a lot given your int'l travel patterns.

In my mind, the biggest thing you'd be missing by not going to PM is the award redeposit fee waiver if you tend to book lots of award tickets. Easily the best PM benefit for me by far. But if that's not a big concern for you, then I would stick to Gold for 2 years for sure.

Of course, if there's any way you could push for PM this year and still fly enough to keep GM next year, that's even better.