Hello All. I am modifying the warlock Subclass The Fiend in a few ways and need help

• How to replace current warlock saving throws Cha with the Int Save
• Add spell points at each level to give (4, 6, 14, 17, 27, 32, 38, 44, 56, 64, 64, 64, 64, 64, 64, 64, 64, 71, 71, 71). This is a fixed number
• Replace base warlock skills with new sets of skills (some may overlap)

We cannot affect base class features in the subclass homebrewer, and we cannot create new base classes.

Dratz. And there are no subclasses that swap out proficiencies?

Any subclasses that add a paladin like Improved Divine Smite (i.e, bonus damage to weapon attack)?

No. Subclasses add to the base class features, they don’t replace them. (For most classes, PCs don’t choose a subclass until 2nd or 3rd level, mostly 3rd. So most characters would never be able to use a feature like that, so they don’t make any subclasses that swap out proficiencies. Lots of subclass automatically grant bonus proficiencies though. 

Is there a subclass like that for Warlocks? Yeah, the Hexblade. They don’t get a feature like improved divine smite, more like regular smite where they burn Pact Magic slots. They can also use Cha for their Melee Weapon attacks and they get proficiency in medium armor and all weapons. They can also raise a Spector to fight for them.