General reason:
There are powerful tomes in the game that would justify limiting their reproduction via the printing press system (IE: Grimoires, Special Stream summons). But there are those that exist simply for the flavor of it. Im listing a few that you could consider adding to the exception list of the printing press. As it stands there are only three magical tomes that could be reproduced via the printing press (Manuscript of the Silent Hand, How to Sing in C Major, Cormyrian Book of Clowning). These three books while being able to be reproduced via the press arent that exploitable, being 2x2 and being unable to be placed inside the book bag makes them cumbersome to carry around for the niche benefit they give.
Book Bag Storage:
Consider some of the books listed to be stored in bookbags. Currently only nonmagical books can be stored. The 2x2 inventory tax can become a pain if these RP books circulates around.
Upcoming Dweomercraft change:
If the dweomercrafting update includes a UI that could easily redescribe an item (copy description from previous item option). Consider this suggestion moot. It might be a better solution as it incentivices dungeon exploration than simple printing on the press
Here's a listing of tomes that I suggest be reviewed for reproduction using the printing press:
Prayer to the Overgod
These are perfect RP toola that a cleric or a faithful may redescribe themselves. I have always been fond of using these for making said books, but ever since their ban on the press, I just write my stuff on plain books. The prayer/day is nice boon to have, not really all that powerful. The unlimited light is also nice to have since you can change glow color with streams.Elemental stream books
The basic earth, fire, water and air. These streams are common enough that making them reproducible wont have much of an impact... unless you really want to cheese the game and store pages of pages of inventory of these books to have basically unlimited summons/day in the low levels. They die easily enough that by level 10+, making use of them becomes moot. These books are perfect for whatever summoning based lore one wants to the game.Minor (School) Studies*
These books are perfect for a scholarly mage to alter. Can be a lecture, or a simple introduction to the spell school, the applications are endless. Though you might want to consider raising the UMD tax on these when they become reproducible. Most of these books have 3 spells, considering that scrolls are better overall (1x1, weightless, local merchants have them), I dont think it will be an issue.Book of Nature Magic: Volume IV*
The only thing that this book has going for it is the Ultravision and Barkskin are cast on a slightly higher spell level than your regular scroll. But these spells are already widespread and readily available even for the mundanes. This is the perfect book to write about flora and fauna, of exploration, and whatever naturey thingy you can come up with.Book of Souls*
Ok this might be a bit too overpowered, and may trivialize death more. Its a fine choice of reflecting your character's fealty to a god when reviving someone from the brink of death. The "Character uses this book" can also be a start of an interesting conversation.Magitech Manual
Saboteur's kit exists, they have more functionality too. The 3x crumble this book holds is really a non-issue when reproduced. Its also a good template book to have for golem/anti-golem lore.Book of Curses
The perfect book for one dabbling in the nefarious arts of necromancy. Bestow curse on a book? Not an issue, its a DC based spell with very little benefit, the DC is only going to pass on a roll of 1 anyway as its cast off an item.
* These books might be problematic to reproduce. You can consider an additional tax in a form of a new crafted ingredient that works with the press. (IE: Magical Ink?). Can consider dumping greater catalysts in to the mix to make their reproduction a bit harder.
TLDR:
Books are great RP tools, but they often only left in shelves to never see the light of day after they have been read. We can add more flavor to these things by being able to use these RP tools from time to time, and the feedback on the combat log can even spark meaningful interactions. Allow us to reproduce these magical tomes to reflect more of our character's interests.