I loooove collecting the spells in Ultima VI and filling out the spellbook. I also LOOOVE the painted scribe style icons for spells in Ultima IX. I also love the idea of having to learn what each color of potion does (even each game as a randomizer option).
I found binding spells with reagents in tshe circle in ultima IX to be a bit tedious, and how inventory space reagents take up in ultima IX (non-stacking) as well as their weight in ultima VI, make it a bit cumbersome. though in theory I love the idea of reagents but think they required too much micromanagement.
For my ultima VI fan recreation project Age Of Singularity, I am working on a kind of compromise system as the default. Here's a concept I whipped up for it; the idea is that spells will auto use reagents needed if possible, and reagents don't have weight, but have their own inventory maxes, the capacity of which you can upgrade, similar to a zelda bomb or arrow system.
This way you don't have to worry about them weighing you down to the point you avoid dealing with spells altogether, or manually managing them, as long as you collect them. I also want to have a "prepared spell" option, where you can store prepared spells in their own place, thus creating the desire upon finding your 41st nightshade to say "Well, I can leave this here, or I can prepare SOME spell, so I have room to get this extra nightshade" - which could encourage players to explore different spell types as well, AND to use them quickly.
I also want "spell-list profiles" where you can be like "okay, I'm at the spell pentagram. Hit the button, and it will prepare my thief profile - magic lock, magic unlock, silent movement, etc." and assign them to a radial or something.
Though I also want people to be able to use spells by intoning their words even if they have not "bought" or "learned" a spell.
Also in ultima VI another cumbersome thing was having to equip and unequip the spellbook all the time to cast spells in the middle of combat, so having it always available, like with a radial or hotkey, MAY be a cool idea.
And one image here for a "full spellbook" screen:
