It all looks pretty solid. I really like the mechanism of divine channeling. You're pretty good up through the first 10 levels or so. But after that, it starts to get somewhat dull-- all you get are bonus feats and incremental improvements to existing abilities. I respect the desire to adhere as closely as possible to the original class, but... well... the paladin has 6 levels worth of abilities.
The versatility is also a tad lacking for tier 3. Smites give you a small damage boost, but not enough (+20 damage at level 20!... does not compare to spells and maneuvers from ten levels ago). Lay on Hands gives you pretty good healing ability, but in-battle healing is weak. Having spells helps, but the list is still kind of 'eh,' especially when you have to consume spells to power your class abilities. Most of the time, you'll be smiting.
To address the points above, I suggest you add more high-level abilities. Rider effects on smites might be cool to see, as well as some of the lay-on-hands status cures you mentioned. Out-of-battle abilities might also be a worthy addition-- say, zone of truth as a SLA.
Just my two cents.