Not sure about current state but i used to play this way many many times about a year ago. It depends on a version, but usually it is quite playable
If you could tell me a version that is quite playable so I could test it, compare to the recent versions and help fix whatever is causing these issues (if there is indeed any cause related to the mod), I would greatly appreciate it. I guess It also depends on what you consider playable though. De-syncs, even if not frequent (i.e. one every 50 turns) have the potential to break several things in the game.
A few of the issues arising from de-syncs that I experienced and remember include (all of these using VP only or VP+EUI in recent versions):
- "Controllable" Caravans/Cargo Ships that are bugged and don't let you end your turn (to solve you have to delete the unit, still have a save with this, it was very hard to find the bugged caravan as the game did not let me know why I could not end the turn);
- Bugged units, whenever they attack the game crashes for all players who can see the battle (to solve you have to delete the unit);
- Naval units end up in the land, or land units in the sea (to solve you have to somehow move them back to their domain);
- Related to the previous one, units teleporting all over the map randomly;
- Units simply disappearing, e.g. after advancing era if you have vassals you gain a considerable amount of units near your capital. In one de-sync we had, all of those units disappeared without leaving a trace;
- Units losing their banner that indicate their position, and that can move through other units while generally they should not be able to (I simply deleted the unit when this happened);
- Unit randomly gaining insane amounts of XP after a de-sync.
This is obviously anecdotal, and from our experience all of these happened more frequently to the players that were not the host of the game. These were all in games with 2-4 players + 4-10 AI in Standard or larger maps. We've tried everything from playing in LAN, to using dedicated servers, to playing through Steam, to connecting directly through IP, to using more powerful computers, to changing LAN cables to new CAT6 cables, to using better Ethernet switches, but these still happen from time to time. We are simply dealing with it. Mods or not do not seem to affect this at all, we initially used to play without mods and the issues were the same or even worse. In fact there are various MP fixes that the community is putting into the VP mod, so it is probably better to play with it, than without.
We only really do not have issues at all when playing in small maps with a few AIs.
I never report these in the github due to them being caused by network de-syncs. As far as I know and talked to Gazebo we do not have access to the Civ5 netcode, so I am pretty sure there is nothing we can do except deal with them with reloads and whatever means we have.