Basics on stats
At low levels, ninja can be a hard job to gear. Your hate-keeping tools are minimal, your spells take a long time to cast and have low accuracy/attack, and you only have utsu: ichi. Essentially, you'll be reliant upon your co-tank - if you don't have one, there's pretty much nothing you can do to make ninja pre-ni a success. As such, I'll focus more on 37+, where solo tanking and DD roles become more viable, thanks first to Utsu Ni, then the elemental wheel, and eventually due to access to strong DD and haste gear.
Where a piece of +int, magic accuracy, or magic attack gear is listed, this willl normally be for the elemental wheel - your elemental nukes. Like a blm's nuke, these deal damage based on your magic attack, magic accuracy, and intelligence stats, with your ninjutsu magic skill affecting their accuracy. These are very potent between level 40 and 55 or so - after that, their effectiveness drops off compared to melee DD. At higher levels, pieces raising ninjutsu skill might be used to help land enfeebles.
When gearing for melee DD, you have a few different stats to balance. The main ones will be attack and accuracy - accuracy, obviously, to hit more often, and attack for more damage. Raising your attack is more effective, generally, than raising your strength, due to how damage calculations are worked out. For weaponskills, the focus shifts a bit more onto the modifiers of the WS in question - for most katana WS, these are str and dex. However, attack can also be effective for WS if available in large amounts (e.g, O-kotes). Dex also helps with accuracy - +2 dex = 1 acc for katanas - but it's rare to find places where you could gear for dex where more accuracy isn't available. And remember! Ninja isn't like warrior or other jobs which can tear monsters apart with a huge weapon skill. Our DD potential comes from a steady stream of hits, with weapon skills providing small spikes.
Haste is also important, especially in large amounts (generally, 10%+). The way haste is calculated means that it gets better and better as you add more, so while 3% alone may not be a big upgrade (such as Fumas at lvl 39), it's increasing availability at higher levels, plus March and Haste spells, makes it highly valued. Of course, haste is pointless for DDing if it only means you miss the mob faster, but it also has an effect on reducing your spell re-cast timers as well as the delay between melee attacks.
Evasion in exp can be a hard thing to use properly, but is worth considering, especially for certain level ranges (between 40 and 55, I found using an evasion build and ninjutsu nukes to be an amazing way of tanking and DDing at the same time, without taking much damage). If you find yourself holding hate comfortably, it can be worth swapping a few pieces of evasion gear in to make your life easier. At high levels though, it's generally reserved for soloing, or tanking in low-man events or certain NMs, such as Charby. +agi also aids with evasion, with two points of agi raising evasion by one. Also, note that evasion and evasion skill are slightly different.
Enmity gains increasing importance at mid-high levels (after the wheeel stops being so effective), and then again for end-game. In exp, it's worth using if you don't sacrifice too much in terms of DD stats - for example, I'd say using Eris earrings over Spike earrings makes sense, but I prefered haubergeon over Arhat's Gi. The mid-high levels in exp can be very hard on ninja. Popular exp targets have low defence, and DDs gain their strongest weapon skills and such - e.g rampage. It can be hard to compete on pure DD terms, so making using of enmity will help.
That any help? It ended up being longer than I anticipated.
Edited, Jul 31st 2008 12:35pm by MithraDooom