- Supposedly Weapon Masteries work as multiplicative modifiers, when it comes to damage (compared to it being additive later on).
- Leap Attack is presumably always hitting.
Anyway, Leap Attack still has some other nice properties, mainly huge +ED% bonus and fact that it ignores Iron Maiden curse. For the most part it can be slow, but it is a reliable attack and with right weapon it can one shot monsters, even in Hell. I decided to go with 2 handed swords and a shield. Those swords have great range, even when equipped in single hand and that helps greatly with range checking, where leaping is often inaccurate. In Classic, max block is almost free and it helps to mitigate some damage you take, while Leaping (you can be hit by monsters while in air). I used Leap Attack on right mouse button, combined with Alt: highlighting loot disables targeting/name locking, meaning you can do much shorter leaps than normally.
In Normal first nice 2h swords can be shopped in Act 3. In Nightmare I gambled for Flamberge with fat damage and in Hell I used all Charsi quests for imbuing Zweihanders. I spend some time farming Sewers in Act 2 (both in Nightmare and Hell) for XP in order to gain enough stats to equip those weapons. When it comes to skills progression, I just started with Sword Mastery, then switched to leveling Leap Attack as soon it become available, grabbing other one point wonders on my way. I even started leveling Whirlwind, but never used it much.
When it comes to other gear, I had luck with shields. First I got Bone Shield of Deflecting and soon after that lucky drop provided Sigon's Guard. I collected all rings and amulets and rerolled everything via cubing, which came handy. I got nice helmet/boots via shopping, sadly didn't have much luck with gloves (I even gambled for them in Hell). Below is collage showing all gear, stats and skills.
When it comes to challenging parts, Arcane Sanctuary and Flayer Jungle were two worst locations for this build. Stacked Ghosts or swarming Flayers doesn't really work for Leap Attack - it is just too slow of an attack. On the other hand, all fights against act boss were trivial - I didn't use any rejuv if I recall. Bosses have hard time rotating, while you leap over their heads. Speed of Leap Attack is also unaffected by slowing effects like chilling (looking at you Duriel).
If someone is looking for nice off-meta build, I can safely recommend Leap Barb in 1.05b if you have patience for it. Mana wasn't too much of an issue, I didn't spend any points in Energy, just some mana leech is enough.