Well, for starters: what's gonna be the spell list? Cleric + paladin or a much smaller list? Mystic Ranger's big problem is that you get new spells up to 4th level, and don't get anything else beyond 6th level unless you go Sword of the Arcane Order, which then gives you up to 6th level Wizard spells.
Second: nothing seems to be removed or replaced. Even the mount is there, and it's as front-loaded as before. Basically you're there for the spells, which makes it Cleric-lite, except you don't get all Cleric spells. The gist with Mystic Ranger is that it delays it's combat styles in order to get spellcasting; the Paladin doesn't get anything delayed, which is a blessing and a curse at the same time (you don't delay stuff like Divine Grace, but at least you don't delay their smites either).
I can't say anything else, because you're quite obviously focusing on making it a sort of "Mystic Paladin" (heck, that's what you're naming it), so aside from probably delaying Divine Grace two or three levels, it fits. The problem is that better spellcasting doesn't solve anything else: smites remain per day (meaning you'll still save them), the mount will still be more powerful than anything else, and Remove Disease will be a bit pointless since you still have it as a per-week resource. So, as a Paladin "fix", it's not entirely powerful, but it's undoubtedly better than a core Paladin just because of the increased spell slots. Problem is exactly what spells will go later (probably Flame Strike, Righteous Might, Divine Power and all the nifty cleric spells anyways).
What's gonna redeem this is the spell list, so make sure it's really, really good; if it scales based on other supplements, it will boost the Paladin immensely.