I think it is a good idea to make grinding more bearable, but it all depends on the reward. A reward that is too good will make doing it necessary and 'encourage' grinding, which is what I think will happen, as there will certainly be 'shortcuts' available using Tibia Coins (like a prey hunting task card to improve reward for 50 TCs), and they will want it to generate revenue. On the other hand, if the reward is not good enough, it will be just some dead feature in the client.
Also I think that it should not be added as another option in the client, but maybe as an ingame quest or something. I think there are already enough options in the client like charms/preys/rewards/tournament and the client is getting crowded with stuff.