It wouldn’t be too hard the reuse similar design elements to make SRD based ones for other classes. I do see the design breaking down after level four - just so much more added complexity and options.
I was reminded as I had my morning coffee that one of nuances of design is not to introduce solutions to problems a user doesn’t have context for. They could have put a shield with a holy symbol on it in the box, but now you have to explain why the Cleric needs that one instead of the Fighter, before they may have even had to face the choice of “do I hold my holy symbol, my mace, or my shield?”
Compare that to the player whose has gotten invested in D&D, wants to create the level 4 character sheet for their beloved Jerome the Cleric, so gets the SRD or PHB. That person is now invested in Jerome. Imagine the reaction when they read the cleric class description and other item details, read about how for 5 gold they can have their holy symbol on their shield, or realize they get to pick a Feat! Then they discover War Caster!
Everyone here knows that little serotonin kick in D&D of “my lil guy gets to do new stuff! And I get to pick what that is!” Imagine how much more fun it would have been to fill out a character sheet for the first time when you actually had context for 70% of it and the stuff you didn’t was you learning all new, neat things your character can do.