I guess it would be too much trouble to keep the Shadow Pokémon subplot given the circumstances required to purify one of those. Would have to either sneak Celebi into the story or have Teejay travel to the Orre region's Relic Forest in order to purify Gardevoir. And since the notes for the Purify Chamber weren't much help in the original series, it'd be too big of a deviation from the main plot. So I understand your decision, and will wait to see how much that helps move the plot along.
On a side note, I really enjoyed the extra bits of comedy in this one. And it's interesting how this version's Gardevoir has an underdeveloped sense of right and wrong, and joins Teejay over Sara for personal reasons. I have a feeling that attitude of hers will get her in trouble someday...
Looking forward to the rest of the series. Let's keep that momentum going!