Ath'kethin
Elder Thing
I don't allow any casters in my campaign except the Warlock, so the bard is a non-starter for me. Nothing personal.
I do agree that the limited offensive choices make the "full caster" aspect more palatable, but I still argue for a reduced capacity at the higher levels of spellcasting. -- Currently, the bard feels more like a subclass of wizard than the inspired sum of knack and knowledge the archetype presents. Reducing his caster level would better contextualize his trope. #twocentsBard is 3rd on my list of best designed classes. A strong but limited spell list (especially with the limited offensive choices) makes the "full caster" aspect not as overshadowing. Has the superior "spells known" mechanic (compared to the stronger but problematic preparation mechanic). Spell secrets is a wonderful mechanic to leverage D&D's list-based design. The subclasses are distinct, but both strong and defining. (Cutting Words is a particular standout.) Expertise and Bardic Inspiration help demonstrate the "knowledgeable" trope without needing to use spells, which is an attractive early level feature.
Make it Intelligence-based, and maybe swap in some warlock invocations for bardic inspiration, and it would be a superior generic spellcaster than the actual wizard class.