I've been playing this new testing version for couple of days now, and I thought I'll post my impressions after playing with USA in sandbox mode. I have very high volatility, no-units start, complete victory, new unit trading mode checkbox unchecked and everything else as default settings if I remember correctly.
First of all, there's a huge improvement on the speed. Around 1960 game still runs less than 10 seconds per day even there's lot of big wars ( USSR vs UK, USSR vs West Germany, USSR vs Spain, China vs France and India vs France ) and few smaller ones and lots of units moving. I haven't encountered any stacking issues at all, but there's some issues with pathfinding in Arctic Ocean with merchant marines. AI nicely scraps units if they get stuck, except after Egypt went to dictatorship and broke all agreements, which left minor traffic jam outside Egypt's national waters.
Economy seems to be changed quite a lot too. Maybe I'm doing something wrong, but it's impossible to sell anything at a profit on the world market ( at least with USA my production costs on all commodities are higher than world market prices ), so this takes some adaptation to get used to. It's still possible to increase your GDP/c though, but it's significantly slower and takes more attention than it used to. I dont know if this is WAD, so maybe developers could shed some light on this one.
Military AI in general seems better than it was. Europeans dont send their troops to some out of supply place in Canada, and NATO is not having a summer vacation on Crete or some caribian island. Unfortunately your own minister still generally ignores your theater settings, but setting units to path around the countries where you dont want him to send units seems to do the trick.
North Korea and North Vietnam have both been eliminated like usually, and I think neither was allied with China or USSR. I did not participate in either of these conflicts. I also forgot Israel vs. Egypt war, and had no troops on Israel soil when DOW happened. I gave Israel about 300 light infantries, but Egypt massacred those swiftly and captured all ports before I could make a landing, so Israel got defeated too. Nice blitzkrieg Egypt
UK managed to conquer some land from USSR by attacking from South Korea, and currently it seems like USSR can't push them back. All USSR attacks in Europe has also been stopped and pushed back, and there seems to be very little progress going on on either front. France seems to be making slow progress in China, and currently have conquered about half of China's landmass, and has about 230 million population. India on the other hand conquered some land from south-west Asia from France, but after that battlelines haven't moved. Probably worth noting is, that I have only participated in european defence, and all asian conquests are done by the AI nations. But I started the game without units, so that changes balance of power a lot, and USSR with it's starting units is a much harder opponent to crack. If I could suggest something though, maybe increase spawn rate of guerillas, so that conquests would not be so easy. At least in areas with high population, guerilla activity could be much higher than it is now, and long dragged wars could slowly turn to defenders favour.
I didn't notice much difference in diplomacy, except maybe more of those annoying trade offers, where other countries try to buy commodities cheaper than it costs to produce. I can understand that my allies with high relations try to leech, but when random countries I have no alliances or anything to do with try that too, it seems a little weird. Maybe this is because world market prices are so low, but why they even want a trade deal when world market is in excellent supply? Some button for auto-decline all offers where offered < requested maybe could make the game a little more user friendly.
All and all, testing version of the patch increases game speed a lot, and also at least in my machine it is really stable too ( not a single crash ), so job well done and hats off to your coders! New economy model leaves me a little disappointed though. It's certainly more realistic that I can't set my domestic prices to 1000% anymore, and just cruise with 0% taxes and max social spending, but when world's most industrialized and technologically advanced nation can't sell anything at a profit, maybe some tweaking is still needed.