Well, it depends on how they implement it. I see both sides as I have FSH/BTN/CUL/ALC all 50 and wouldn't want that time and energy negated by NPC's...but also sometimes would love if my NPC could go fish a couple things up while I gather on btn the other mats.
1. They could make it hard for your retainer to level a DOH. This would end up discouraging over-use.
2. They could put restrictions on your retainer that allow it to only do 'one thing'...or 'one thing at a time. So the player would have to choose between allowing the retainer to go out and gather, hold supplies, or sell/buy stuff etc.
3. They could limit it to lower quality items and/or lower zones...so basically, retainers just get the commonplace raw mats....with maybe the occasional chance for a super-rare item ONLY retainers can find. (This way, they aren't directly competing with gathers).
4. They could make it so that they make the basic mats while you are out of game...but that they can only make 'x' amount.
5. They could put long cool-downs on NPC abilities so that people can't just constantly spam them.
6. They could even make it that the NPC has to come with you and assist you while you gather, so you still do all the work, but the NPC raises the amount of chances/items/ or HQ's you might find.
7. They could cap NPC levels to that far below Player level cap. So NPC's can only gather grades 1-3, but players all zones/levels.
