Why is Palliation Accord recieving errata? It's not an especially oppressive or popular card. I think the idea of an older and mostly forgotten card getting a small amount of power increase is nifty. One of the things I love about MtG is the way older cards can have new and interesting interactions with newer mechanics. Would y'all reconsider this change, or at least help me understand why its neccessary?

The problem is the counters on the card have a function which doesn’t match what shield counters do. When old cards match functionality of a new ability, we’re sometimes willing to errata it to the new named ability (and thus enable synergies with the new mechanic). This is the opposite issue though, so here we keep them separate to keep the card working as designed.

Will shield counters moved from Palliation Accord (Dissension) onto a creature interact with the Shield Counter mechanic in New Capenna?

The Streets of New Capenna rules update is going to change the shield counters on Palliation Accord to palliation counters so there is no confusion about them.