I tend to agree with DG at least on the Phil Stone issue. I love the card, I've used it to beat Ambassador before, but I was honestly probably quite lucky to do so, and this board doesn't have any other trumps for it either. The problem is that, although the Phil Stones will be worth a zillion dollars, you'll almost never be able to get them into your hand. So you'll get maybe two provinces but just be blown off the board. The GH+Vineyards idea is interesting...
But the thing is, on a board like this, I'm not so much going to have a single, grand net strategy going into the game. I have to watch very much what's happening on the board and what my opponent is doing and adjust accordingly. A lot of boards, that's not as important, but with something like this, with a lot of directions and potential interaction and different speeds, it's critical