THANK YOU for reporting this, I've made a last update that made it into 2.0 that will resolve it for you. Good timing on finding this!
From the 2.0 notes:
-A new Network Sync Performance Settings section has been added to the General tab of the Settings window. Generally players will not need to touch these settings, but it provides some advanced configuration problems to improve game sync transfer rates for those players who have performance issues with the default settings.
In your case, you'll want to go back to "100 Messages" and with Skip Batching turned on, and you'll be back to the way it was before. Clearly that works best for you, but for a lot of other people the new way is better. So now the settings tab has options where people can use the style that works best for them, and the tooltip in the game explains it all in more detail:
About Network Sync Performance SettingsThis section will help you improve the performcen of loading/syncing games across the network, if you have having trouble. Please note that this will have NO effect on in-game performance, just on game syncs. The default is N/1200 Messages, with batch network sending not turned off, and this will work well for most people.
However, for those with very fast connections, the old default of 100 Messages, with batch network sending skipped, may provide better performance (these are the old defaults). This will vary depending on your connection, though, and some people had extremely poor connection speeds even on very fast connections with the old defaults, which is why the new defaults were added.
******** OTHER OPTIONS ********
- 1 Msg. should generally be avoided, but it might work on some connections.
- If 100 Msgs. gives you some slowdown, but not a lot, try 1000 Msgs.
- N/2400 and N/200 and N/1600 create fewer messagse than N/1200, and may provide better performance than N/1200 on fast-but-not-super connections.
- N/800 and N/400 are really only for very slow broadband connections or lower.
******** IN SUMMARY ********
The short explanation is that if the new default gives you slowdown, then try the old default. If that also gives you slowdown, then you can try the other entries here.
******** WHAT SORT OF CONNECTION TIMES TO EXPECT? ********
Here are some common connection time estimates (which may naturally vary some, but you have problems if it takes more than twice as long as these stated estimates). Bear in mind that these estimates are for a fullspeed transfer, which might not be achievable because of packet loss and other network conditions, or based on the Network Sync Size you choose.
Host 100kbps upload, 1 Client, 500KB savegame: 41s
Host 100kbps upload, 4 Clients, 500KB savegame: 2m, 44s
Host 100kbps upload, 1 Client, 1.5 MB savegame: 2m, 3s
Host 100kbps upload, 4 Clients, 1.5 MB savegame: 8m, 12s
Host 300kbps upload, 1 Client, 500KB savegame: 14s
Host 300kbps upload, 4 Clients, 500KB savegame: 54s
Host 300kbps upload, 1 Client, 1.5 MB savegame: 42s
Host 300kbps upload, 4 Clients, 1.5 MB savegame: 2m, 47s