Warlocks in 5e are boring, mechanically speaking

I'll put this out there to anyone who's reading this: this isn't a complete system yet. I'm still adding/taking away things from it. If you have a suggestion, lemme know.     However, thematically they are really cool. You sell your soul so you can attain powers you normally wouldn’t have. It basically means a farmer or peasant can be a powerful magic user. You could be an illiterate idiot and be able to kick it with some of the best Mages. However, they’re still stuck in that Vancian System of magic, which is painfully fucking boring. I get it, it's safe, tried and true. But before all you neck-beards cry about "muh balance" just hold your horses. I want something a little different for my games. I felt it was a good idea to create something for my Warlocks in the same vein of The Last Gasp. Below you will find my little magic system hack for Warlocks in 5e. It may seem overpowered at first glance, I don’t really give a shit about that.

Spell Casting for Warlocks

The Warlock has 1 free spell per long rest, there are no rolls needed. Beyond that first spell, things get a little hairy. To cast a spell after that initial one, the Warlock must first Save vs Magic, meeting or exceeding a roll of a 3 on a 2d20. You account for each d20 roll separately. Both have to fail for a mishap unless a natural 1 is rolled. No spell slots are needed using this system. Whatever spells they know, they can cast as much as they want. However, each time they cast, the save increases by +3 for anything 1st level and above. Cantrips are exempt, they act normally.

Both Fail- Conduit of Cosmos.
Single Natural 20- The spell's power is maximized. Double Natural 20's- As above, the next spell is free, and the save reverts back to 1 for their Save vs Magic roll.
Critical Fumble on 1- The spell autofails and the referee will Cast the Bones. Compare the difference of your second roll to your spell save. If above the save, you get a bonus to your Cast the Bones roll, if below, you take a penalty.
Ex: You roll a 1 and an 18, your spell save is a 12. That means you get a +6 to the Bones. Done fucked up, 2 Critical Fumbles- That Which Should Not Be will automatically be rolled. Schrodingers Cat, 1 and a 20- Demands of the void will be rolled and the spell is maximized. Furthermore, during a short rest, the warlock must roll a 2d4 to see how much he reduces his save by. A long rest resets it.

My Line of Thinking

I like to think that the patron's powers are limited to a certain degree. That if you cast a shit ton throughout the day, it'll be harder for you to so the more you attempt. These things that grant power to the Warlock don't have a limitless supply of it. Or maybe they don't want you to have that much and they like to toy with you. Either way, that's what this represents. Sure, spell slots represent that limitation in a way, but it doesn't show that you can push your patrons limits beyond what they're capable of, bringing chaos into you and your companions lives. Does this mean you'll have to do a little more book keeping? Yeah, a little more. But this just means that you'll just have a more robust magic system for your game. It'll be a risk to cast a spell each time, which in my eyes is what ALL magic should be. Magic isn't your friend, it doesn't want to be used. It's a living thing. For all intense and purposes, it wants to rip your atoms apart, and spread them throughout the void. You just chose to tamper with it. Knowing that, you accept your fate.