I love a good token deck, and Isshin seems like fun! Have you considered playing more into doubling triggers on your opponent's attacks? Revenge of Ravens is a very good Propaganda-type effect for Isshin. You could then lean into Eiganjo Uprising or Genesis Chamber and goad/force-attack effects, with cards like Goblin Spymaster, Karazikar, the Eye Tyrant, Kardur, Doomscourge, Vengeful Ancestor, Baeloth Barrityl, Entertainer.

In terms of protection spells, Inkshield seems like a great effect in this deck.

Paladin Class seems a good fit. protection from spells on your turn, an anthem, and a massive double-boost on the last effect. And Linden, the Steadfast Queen also seems like a strong effect to maintain your life total while your team is tapped down. Angelic Exaltation is an all-in Exalt effect that lets you get in for a lot of damage with one creature, should the need arise.

I had a few Revenge of Ravens type effect in my initial draft of this deck, but ended up taking all of them out in favor of more aggro stuff. Angelic Exaltation is another one that I removed in favor of more go-wide effects. One of the reasons Isshin is so great is because he's so wide open. A forced combat/goad/pillowfort/politics theme is definitely possible!

Inkshield is already in the deck. :P

As much as my lifegain loving heart loves Linden, the Steadfast Queen, I think the triple-white cost is a bit too much for three color manabases. That being said, she does seem like a good inclusion to offset the inevitable backlash from other players that I've attacked. Added to maybeboard!

Paladin Class isn't something I thought of before, but it seems like it might work. Gonna have to add that one to the maybeboard, too. Thanks!