I'm actually doing this one for the opposite reason of most.
Talking to people about "Rainbow Falls", I learned that it was at best one of the season's most divisive. The thing is, even after re-watching, I think this is a pretty good episode. Most of what I said in my original review holds up, though this second time, I don't like it quite as much. Still, it's a reasonably entertaining episode that reinforces Rainbow's values.
One major criticism many have towards the episode is in regards to Spitfire, whose personality seems to have grown more and more unpleasant by the season. While I don't feel this is necessarily out-of-character for her, given that the most we saw of her was in Wonderbolts Academy and her personality there is consistent with hers here, her "change" at the end is a bit too rapid. In all of the other "rainbow" episodes, a character is inspired by the episodes's protagonist. In "Rainbow Falls", Spitfire has a random change of heart after hearing one speech by Rainbow. This was done much better in "Wonderbolts Academy", where the reaction time for Spitfire was longer.
At the same time, the reinforcement of the element of Loyalty within Rainbow is still there and still interesting, and the episode serves as a nice culmination of all of Rainbow's character development up to this point. However, that perhaps reflects on one of S4's issues, in that there's no proper character development for the main characters. At this point, Rainbow's begun to stagnate, as have her friends, and this affects all of the key episodes. "Rainbow Falls", being arguably the blandest of the bunch, suffers the most from this.
Indeed, "Rainbow Falls" probably has the least personality of any of the rainbow episodes. As a pretty good MLP episode it's not bland in its own right, but compared to those around it, this episode comes a little short. There's a relative shortage of jokes, with the plot again driving the episode. Thankfully, the plot is mostly strong, but the conflict probably wouldn't even have happened if Ponyville's team made any sense. If Ponyville has to resort to putting non-flyers like Bulk Biceps or non-athletes like Fluttershy on their team, why are they entering at all? Ultimately, it works out because it allows Rainbow to reinforce her loyalty.
Meanwhile, though, there is a decent amount of action. Stuff DOES happen, and there's some funny jokes on top of that. It retains the elements that make all of the key episodes work, though I've gone over those a fair number of times. Most of my focus in this second take is negative, though that's mostly because saying the positives at this point would be repeating myself. It's also because I mostly did a second write-up on this episode just to address some of its weaker parts, which I will be doing again with "Testing, Testing, 1, 2, 3". "Rainbow Falls" is still a pretty good episode, though it's not as good as I initially found it to be. Next, "Filli Vanilli".