I've been playing Domination a lot lately (really the first time since CoD4), and I'm that solo player with 2.0 K/D (in Domination, 1.67ish overall) > , 350ish SPM, around .9ish W/L, and is always capping/defending flags. I seem to be the rare player that is pretty decent.
GT: xFrostxPhoenix Now Playing: BF3, DC 2 Waiting for: MW3,Skyrim, ACR...Monster Hunter is the **** btw.
I mostly play solo and the majority of my time is in 6v6 TDM, KC, and Domination, where I have a win percent of somewhere around 58% (so around a 1.4 W/L). In free-for-all (where everyone is a solo player, essentially), I have a win percent of around 95% (19 W/L).
In other words, it is quite hard for a solo player to get a high W/L in team-based modes; comparing solo players and team players using W/L as a basis is difficult because as a solo player, skill does not necessarily correlate with winning the game. This applies even more in Ground War, where there are more players on your team that could potentially drag you down.
Well the difference depends on their skill level and it's that simple. Trying to find out via their stats is just an awful idea. I've trounced my share of parties of braggarts with 2+ KDs because they didn't have cooperation, though. It's really true that excelling in a party requires a few members to take advantage of teamwork.