I haven't found this to be the case. Laning or jungling, being a ranged carry offers the advantage of being reasonably safe as a farmer. Unless you're against a tri-lane or unless you're support picked a support that can't do any actual supporting, you should be fine farming. Her damage is pretty good IMO.
Jungle farming is for when you want to watch the football game while you play, because there's literally nothing to it. AFK autoattacking for 50 seconds every minute. But yea ancient farming can be done with or without wards. Just depends on your needs. Generally with any ancient farming plan, you need to have a snowballer mid. Can't have an afk farmer mid (say, a Weaver or OD...or someone else who doesn't really want to leave the lane to gank) because the solo lane will need help before the ancient farmer is ready to be helpful. If you have someone like Pudge or SF or Huskar mid, you'll be fine most of the time unless they're bad.
My baby can't be expected to carry every scrub comp. Even Jesus couldn't heal everyone. Doesn't mean she's any less divine.