I rate Fahey higher than Miller, but I don't believe they're the same type of player. Fahey would play as a wide player in Trap's system.
Not saying I agree with it, but it's just the way it is, so comparing the two is pointless.
But even if they were vying for the same position, Trap is running our national team like a club. Friendlies are not merely experiments, they are trial runs for qualifying games. Players will not be dropped from our squad because there is a player who could be better, they are dropped when they don't perform, or if a player demonstrates beyond debate that he is superior at club level.
I'm not a fan of Miller, but he performed well against Nigeria, and to drop him would send the wrong message to everybody.
We all ripped into Benitez for dropping Keane after he scored two goals in the previous match while at Liverpool, and now many are upset that Miller has retained his place after an impressive performance for us?
Trap's whole message is that it doesn't matter whether you are a bench player or a starter at your club- if you're doing the business for Ireland you will keep your spot. Whelan and Folan come to mind as players who were not always figuring for their clubs, but have played important roles for us so far, and have thus kept their spots.
Club performances are important, and do tell us a certain amount about what our players are capable of, but it shouldn't be the be-all and end-all.