Can anyone tell me what the importance of experience is?
Experience can come into play during critical situations, like in the final seconds of a close game, or can be the difference whether a player takes a bad shot or passes it. These are the only examples I can think of, and I'm sure someone else can expand on this.
Also is experience is a primary difference in having NT prospects play for the U21 NT?
Experience is less important to NT and U21 managers, as far as I know. Sure they want most, if not all their players to have nice EXP, but it isn't necessarily a deal breaker.
Why isn't experience a transfer list searchable skill?
I'm not sure. Maybe the BBs didn't think it was that important to add it in.
I'm just wondering how effective a team of highly experienced older and less skilled players are against inexperienced higher skilled players.
As for this question, I am also not sure. Other factors such as GS/DMI, enthusiasm, foul trouble, as well as unlucky/unlikely occurrences could change the course of the hypothetical game.