Too powerful? Should there be an activation cost for the scry ability?

I think it was actually a bit too weak, now it might be a bit pushed but it should be okay. Do you think we should try to represent the pro/con aspect of the Old Magic on this card or a different card?

No. Represent the old magic on different cards, perhaps an uncommon cycle. This card just represents the shards power, like with how it effects Shinovar and the Horneater peaks. The nightwatcher is apparently Cultivation's Spren.

Oh, I want it. I recommend tweaking it to say "Whenever you put one or more counters...", so that it only triggers once in cases where you put a bunch of counters on something in one effect.

I don't know if "you put" technically works (which is why I changed it from that originally), but I tweaked it to do the same thing you suggested.

I didn't even notice the wording on how the counters get put, in my case or yours. I think it should work, but it's not as clear as the current wording. That wasn't the important thing.