Lol having both Kanon and Clannad in the tags confused me at first.
This map is hard to mod, in the sense that everything is really neatly made and there are few mistakes to be fixed. That said, I'll mostly be posting stylistic disagreements and suggestions.
[Normal]00:06:893 (1,2) - These look a bit flat to me, try moving the middle node of (1) left 2 grids and copying for (2).
00:09:893 (1) - ^, given that it's supposed to wrap around the previous note. (the next slider is fine since the distance is farther)
00:24:893 (1,2,3,4) - This is a lovely lovely lovely pattern. (so is 01:48:923 (1,2,3,4))
00:29:393 (1) - Not new combo, since all the previous combos were 2 measures long, and keeping it that way would be consistent and fit here.
00:35:393 (1) - ^, though this one is more up to you.
00:57:893 (1,2) - Visually the space between their paths looks cramped, consider moving (2) down and to the left (and 3 as well)
01:19:643 (3) - Consider making this a curved slider, wrapping around (4).
01:33:923 (1,2) - Similar to 00:57:893 (1,2) though the spacing is a little better in this one
The difficulty was well-done and beautiful, my only criticism would be that some of the patterns and sliders felt too horizontally linear, though I guess that helps with readability and ease of play for beginners. All the same, my favorite patterns in here were the ones involving curved sliders- you used them very effectively.
[Collab]00:10:643 (5) - Make this symmetric?
01:03:143 (4) - Consider raising this up about 15 pixels, since a straight line of (3,4,5) is boring.
01:33:923 (1,2,3,4,5) - The angle on the overall curve from (1,2,3,4) looks too flat, consider adjusting to something like this:
01:43:673 (3) - The ever-so-slight hard angle here discomforts me, consider moving the red node down a few grids? Also I don't see why 01:50:423 (7) was made a copy of this slider, it's somewhat unintuitive.
03:05:985 (6,7,8,9,10) - The large arc made by this pattern looks jarring right after the previous one. Make this some other kind of pattern, since a long path of notes was done right before this and right after. For instance, a pentagon/star could work here.
03:11:798 (1,2,3,4) - It's a good idea for a pattern but the apparent spacing looks uneven- by which I mean it'd look better if the start of each slider was equally spaced apart from the other starts.
This diff felt very fundamentally different- almost none of those "horizontally linear" patterns, instead opting to go every which way. It's very fun to play and feels more appropriate for a harder diff, so good job.
Overall, this felt like a very, very polished beatmap set, enjoyable and visually appealing. I don't know what else to say, really, so starred x2; get this ranked soon!