I'm just going to throw this out there but monks have more of an impact than most classes in randoms. Like druids, they're able to flag carry really well thus a large portion of BGs become substantially better because of this fact.
Full prideful and skilled have more of an impact than an entire team of bots.
Regardless of the conclusion from this research, 50 BGs is not a substantial research size especially considering its only a single character. If you got 10-20 people to do the same on a range of classes/gear levels, then you would have an impressive quantitative metric. Just as an example, on my main, my average win-rate is approximately 70% (mostly solo) for most bgs but even with this win-rate on a mix of realms and changing factions multiple times, despite this I sometimes get 5-10 losses in a row as a full prideful player playing to win. Most BGs, the only heal I ever get is from myself yet on the opposite team, I'm constantly dealing with healers everywhere.
Some BGs have full prideful, some are fresh dinged bots with cataclysmic pvp gear, some are grievous and some don't care about winning. It's all random and your class/gear/role have an enormous contribution in winning and your capacity to win. If you put the effort in then you can help in winning the BG but there's often only so much you can do.
As an anecdote, I play SC2 team games every now and then but my mechanics aren't quite strong because of my infrequent commitment to the game to get better yet I perform much better than players at my level, usually gold league. My APM averages at 130, 3-4x higher than the average but even I wouldn't be able to stand against a team that works together and plays well. If I'm lucky, I can establish base expands and sky rocket my macro economy, make a huge amount of units and constantly harass and push 4 enemies at a time back long enough for me to get exponential economy growth or to boost my team but this is rare, I can't do this frequently and most of the time, I can feel helpless despite me having a 90% win-rate in my league.
A recent game I played had their entire team rush us, they killed 3 of my teammates and even though I thought of surrendering right there and quitting the game, I managed to defend the attack when they attacked me last and I expanded twice. This put them behind which allowed me to constantly deny their economy, send dropship attacks everywhere and keep my economy superior. In the end, I did so much damage and managed to get ahead that I won the game, 1v4 in a 1hour long game.
In the end, sometimes you can't do anything to help but sometimes you can. However, SC2 is a much harder game and has a much wider and higher skillcap which allows better players to excel more than a game like WoW where skill isn't much of a factor unless its top end PvE or PvP.