I did not say it was a good idea. I said I would not be surprised. I also agree that it is likely that they will put up a wall between xp bonuses to level 1-20 and xp bonuses for 21+.
I think you are drastically underestimating the item in that game. Sure there is quest xp in LOTRO which does grant decent xp, but skirmishes were changed to have boosted xp on mob kills to get rid of those end rewards and they are one of the main ways a F2P can level easily in the game. Correct me if I am wrong, but the trinket is a +75% xp on mob kills right?