Paladins are alreadt single target killing machines. Why the need to make them even better at it? I might might a smite ability that does less damage but in the form of an AOE or something but then again if they want to do that they can cast a spell,,,which is why they have that option now.
I simply would not allow it. Someone taking ALL those classes is hard to fathom. How in the world would one guy have access to learning all those classes one right after the other? The player would have an incredible amount of abilities from all those 1st level booms.
Im a very open minded DM...
Our last session I had dust particles all in the air limiting the darkvision range to 30'. It worked really well and the players were much more nervous.
I control thunder wave easily. IT IS VERY LOUD! If they are in a dungeon for instance they will wake up the whole place using that spell. My group uses it sparingly since they dont want every room to have all the enemies using bows etx from behind flipped over tables.
You gave almost no information. Do you want to be primarily a caster, an archer, a melee. Do you want to add heals, AOE's, control etc....share some information
Varient human paladin 6 of vengence.
with pole arm master and sentinel feats or
something very different
Bugbear paladin of treachery would be fun and really suite a Bugbear and his crazy god.
Throw in pole arm mastery and he would love the middle of the battlefield
For Paladin I like the improved divine smite at level 11. Id go Warlock and use their spells to fuel more smites after that. Plus some invocations are fun.
As for different races Id probably go with Varient human or Half orc but thats just me.
I know BH damage is broken unless you use the 1.8 newest version. It is a lot more balanced.
That being said I still think the BH would be higher damage unless you are using the Warklock smites from UA.
For my table the Rapier is a heavy broad sword made for piercing through armor and the long sword is a bastard or a hand and a half sword meant for slashing.
The more I think about it the more I think this could be a Fighter archetype.
A fighter with a few roguish qualities and perhaps sneak attack (that does subdual damage), move silently in heavy armor bonuses with martial dice per rest.