I am having a blast with the multiplayer, hacking or tailing other players is a joy that can't be described, CTOS Challenges are great fun too. I couldn't try team matches because it takes so freaking long to set up a session and gather players, I get the feeling not many people play WD on PC, waiting times for any MP mode is quite long.
I've watched a few multiplayer matches on PS4 in a livestream. It did look quite fun - but as it is one on one, it seemed as if it would get old relatively fast. A team version of something like that could definitely be very cool.
As a single player, I don't think I would enjoy the game. I am not a big stealth fan. I do like the emphasis on 'realism', but the way it is implemented feels a bit too much still like it is done in Assassin's Creed. It feels too much like a puzzle game, and not enough like smooth, emerging gameplay for me to enjoy it. But I could be wrong, this is just going by the live gameplay I've watched (also single-player) - some of the missions there felt like the parts of GTA and Assassin's Creed that I enjoyed the least. I think I like the stealth in a game like Uncharted best - it's great when you pull it off, but it's very optional.