I've cracked the code actually. Here's all you have to do, to adjust your opinions for players to be higher or lower than what their average indicates, if you want to conform to CW Cricket Chat concensus.
If you know which of these major cricketing countries the player is from, you can adjust them by tier value. Always adjust tier 1 averages favorably, and tier 3 averages unfavorably. This is because Tier 1 countries have the most deluded fan support on this site, who insist their countries players experienced some special circumstance or other to elevate the significance of their positive performance and mitigate the negative performance, and will argue you to the tooth to. It is useless to argue against such a deluge, regardless of the existence of facts or evidence supporting your negative argument against any such player.
Tier 2 countries have just about enough support on the forum, or value attributed to undeniable historical achievement, that you can't get away with lowering their averages, but at the same time were rivals to Tier 1 countries so you can't increase their averages either, so don't do either.
Tier 3 countries are from countries who were both in recent history very tough opponents and rivals of tier 1 countries, and also have the least amount of support on this forum. For this reason just make up whatever spurious arguments you can to bash their players and lower/increase their averages unfavorably. No one's going to challenge you on those arguments anyway, so eventually your takes will become part of the consensus.
With this simple guide, you too can help build "historical consensus" on the Cricket Web Cricket Chat forum. Have fun! And excuse me while I vomit somewhere...