Tiers, sort of, rank the best players from each team (if fit) in each position. Let's say roughly 12 ranks (coz 13 is a horrible primer number).
Tier 1 is positions 1-3
Tier 2 is 4-6
Tier 3 is 7-9
Tier 4 10-13
My ranking is about how unpredictable the player is to defend against. van der Merve is a case in point. Or even Nowell. You can't predict what they will do, and that forces defensive decisions that are sub optimal. Attack isn't just about what an individual player is good at. If it was, Watson and Kibirige would be scoring every week, more than one try per game. But, other than their speed in space, they offer little else by way of threat. Compare to Radwan or Rees-Zammit. Those damn players pop up everywhere. It is why I suggested Ibitoye would be good for us, as he is the same. It is what made Wade so great (until he lost interest)
and also Piutau.
So, a Tier 2 players is one who ranks 4th to 6th in their position in the league. So, not just EQP players. For example, in Tier 1 I put Faf. Everyone has strengths, but also weaknesses. For backs, it is the ability to force a defence to consider many possible scenarios. For Dobby, his best two skills are lightning fast distribution and support in open play (he always seems to be in the right place at the right time. Neither of those can a defence really defend. What they can defend is the snipe and the box kick, and Dobby is not so good with kicking, so it gives defences less work to do. Dobby's passing can be a bit wayward at times.
A successful attack is partly about dividing and confusing the opposition. That means you have to be good at those things that force the opposition to think hard about what defence they mount. With Dobby and Jacob, the rush defence will almost always work. Try that against Care and Smith and see what happens.
One reason Daly was so good at 13 with us, and one would argue not so good elsewhere, was that he had Cips and Jimmy inside him to distract the defence, and Wade outside him. Similarly, when we had Beale at FB, that gave Daly so many more options.