As I had mentioned in the other thread, I really like a couple of Basic Forests and Hermit Druids over the Stitcher's. It's a little bit slower, but activating a Hermit Druid once or twice is much more impactful than just milling 3 cards off of the top. Without the Hermit Druids, I felt like I had to mulligan aggressively to Bazaar and that kind of doesn't feel so good.
Other than that when I was seriously working on this deck like about 6 months ago, I came to a very similar deck build. Sideboard was slightly different, but that always seems like personal preference. Veil of Summer specifically was a fun card to push through a big turn against control decks.
The one other thing that I've played around with is a splash of blue (instead of white, or whatever other color for SB cards) since it gives you Time Walk and Ancestral.
I have also been playing around with a blue splash in this deck, and it has felt pretty good. The big issue I've found is really that the deck is already so streamlined. There's like 2-3 flex slots in the entire deck.
Stitcher's is one of the best cards in the deck imo, I don't love putting in a replacement that has summoning sickness and requires to be tapped so you can't use it to cast gaak. I do think that mulling aggressively to bazaar is a trap. Bazaar is the best card in the deck, but it isn't needed in every game.