Well, 15 pally / 5 ranger is a pretty solid and dare I say it traditional build.
I can only guestimate since I didn't play DH so far. So please, specialist, correct me.
traditionally 15 Pally so you can get zeal and 5 Ranger for T5 Tempest. Bring DH into the mix and you get SA and might even have enough points to do traps successfully. Maybe T5 DH is possible, too.
For stats,
you need dex 17 to be able to take the TWF line but you do your hit+damage and tactics with str (horc supports that) and cha. Don't make con the dump stat. You need at least wis 14 to cast spells and if you really want to do traps you can't dump int either. So it is pretty attribute intensive.
KotC and Tempest are your main enhancement trees, with SD for a bit of defence.
As for feats probably something like
heroic: the TWF line, Precision, Knight's Training or the matching younterpart to the weapon you carry, ImpCrit, Quicken Spell for uninterrupted heals and buffs,
Maybes: stunning blow for helpless damage, Empower healing but you could go Dodge, Mobility, Whirlwind, maybe Spring Attack, Sneak of Shadows
epic: OCrit, Epic Reflexes, Doublstrike, Harbinger of Chaos, Scion of Arborea or Astral Plane or Etheral Plane (depending on playstyle)
Maybes: Crush Weakness (if you got for helpless damage), Elusive Target
Cheers,
Titus