guerron was probably meaning to state that he/she believes roughly the following for Feral DPS rankings in comparison to other DPS classes/specs:
mediocre Feral (7.2.5) <<< mediocre Feral (previous X expac) =< great Feral (7.2.5) < great Feral (previous X expac)
Simply put, the potential of Feral in comparison to everyone else is not as great as it once was while still being one of the more complex specs to play. While it may not be exactly the case at all, I'd stil say the gap between a mediocre Feral and great Feral in terms of DPS is much larger than it has been in the past. 7.3 changes should hopefully shrink the DPS gap between skill levels and allow Blizz to increase the maximum potential of Feral if deemed necessary without penalized the lesser skilled players.
With respect to the Feral challenge, it really sucks if you don't have a decently high level of crit with the typical builds that are used. Assuming you're a Moonkin, Polarthief, so crit rating is something you likely avoid, and that understandably makes the Feral challenge very annoying. For example, as a main spec bear, I had about 18% crit when I was Feral kitty (since I generally avoided the stat), and using an SR/JW/BT build with Predator instead of Blood Scent was extremely terrible. I was having issues getting extra combo points using Swipe when 3+ targets were up, to where I'd occasionally Swipe 5 times for 5 combo points. Now, the root problem was SR/JW/BT and the fact that Feral was an offspec: the spec works fine (even great) if your gear is tailored for Feral in 7.2.5 as you can generate combo points steadily enough to keep up with the timers without being energy starved, otherwise it plays marginally fine to downright horrible even if you're playing the spec correctly. This is specifically what the 7.3 changes are likely to fix.
For the time being, I'd recommend using SotA legendary ring and Brutal Slash instead of Blood Talons until the 7.3 changes go live with low crit gear (managed to do that 20-25 ilvls ago and beat the Feral challenge with 4pc NH tier with minimal headache), as your energy levels will be more stable to account for crit/OoC dry streaks that will happen with non-Feral tailored low crit gear. In a more general sense, SotA and Chatoyant is likely the best way to counteract bad itemization until 7.3 comes out in any situation, as long as one has access to said legendaries.