Personally, I feel like this episode was more centered in how Konata is actually sensitive to how Kagami feels, which many viewers can possibly be oblivious to (other than the Haruhi concert scene, which shows how much Kagami cares for Konata). Of course, I could be biased because I am a huge KagamixKonata fan.
But I think while the entire love letter scene had a lot of built up and in short-term, it did end up looking like a gag by KyoAni, I do however sincerely believe the entire scene was more a built up to the purikura in the end.
