Well, obviously a lot depends on the specifics, but if I'm a caster I generally have weaker armor, which means instead of six options, I'd have 3 on my turn unless you fundamentally change the nature of the spells. And those cantrips are already designed to stand in for at-will attacks, especially if you've taken a subclass that adds a modifier to the damage.
It still sounds like, to me, you are essentially just giving more powerful attacks to a class, in exchange for being able to do little else. Which does not sound like it would be an interesting class to actually play.
How are options 1 and 5 different? Why do I need more cantrips if I'm barely going to use all of the ones I have? It looks like this ends up being a choice between three options. 1) Become a spellcaster with complex options (defeating the point of the design) 2) Becoming a spellcaster with ritual options and better exploration (which is something most other casters are doing already) 3) Become even stronger in combat.
I'm not saying that the vision in your head is bad, but what I'm seeing reads a lot like "I get to do more damage in exchange for being worse at the types of things casters excel at" And they would likely STILL struggle to get better at-will cantrip damage than a Warlock.