Read "magic" shouldn't even be a thing. Books and scrolls containing magic spells should be written in a variety of obscure, dead, and ancient languages that the Wizard may or may not be able to read based on his studies of said languages. (And, FWIW, anyone else who has studied these same languages should likewise be able to 'read' those same books... or course, doing so would be equivalent to a layman reading deep legalese, or computer code, or similar - they may know the words, but that doesn't mean they have the context to understand them.)
I agree. I have done something similar with
Comprehend Languages, where the ritual is actually a derivative of an older and more powerful spell,
Comprehendere Linguam. The ritual
Comprehend Languages was originally created for simple use for merchant men, low-ranking wizard translators and for general use for legal contracts and the like - so it only functions for the most common current scripts.
Therefore
Comprehend Languages is not able to decipher archaic or forgotten scripts - the wizard PC is now in search of the more powerful version of the spell
Comprehendere Linguam.
I have taken spells even further - since we play in Mystara, specifically the Duchy of Karameikos, the wizard has found out that Glantrian wizards are able to cast more powerful or flexible versions of the spells but at exactly the same level. For instance, the Glantrian version of
Comprehend Languages the Range is Touch, which allows someone else to benefit from the spell as opposed to only the caster.
Mage Armor can be cast as both from the School of Abjuration (current playtest) and from the School of Conjuration (3e).
Mage Hand allows you to summon an additional hand but requires concentration.
Flaming Sphere has additional range...etc
So introducing little changes here and there, which keeps the magic of the setting interesting and new.
Of course now the PC wants to travel to Glantri and learn their arcane casting style so he is saving up on monies for the Great School of Magic and is more than likely going to sell the Adventurer's Guild he owns.
There are ways to keep the cantrip idea without making them completely at-will. I don't think the solution has to be completely at-will cantrips or nothing. There is room for the idea to be implemented in other ways.
I use them in B/X. A mage gets points per day to spend on cantrips equal to INT+ level. Cantrip capacity increases with level just like other spellcasting powers. Thus it is possible to include cantrips without the at-will feature.
Personally I prefer intelligence modifier + level, but that it is refreshed between short rests similar in vein as @
Mistwell proposed with a constitution check to push oneself further if they wanted but with different results (not wild magicky results) if one failed - I was thinking temporary blindness/deafness, headaches - therefore unable to cast concentrate spells, dizziness, nausea, nose bleeds, fainting..etc