with the same idea as Heart of Gold if you are going to make a Youmuu's Ghostblade, you may want to make an Avarice Blade earlier too to maximise the benefit from its passive. Although I think I like it where it currently is since it doesn't really provide much benefit but definately take Heart of Gold earlier. The hp boost realyl benefits you.

since you have amended your mastery tree. You may also want to amend the mastery section in your guide as it talks about the utility tree.

ok, thank you for your post, ill try and fix some things up. but for me, these items work good for me because it suits my style of how i play irelia
i do get how some items need to be changed, and also some masteries

Informative guide but you should take the time to edit the grammar (capitalization, punctuation etc) and spelling in order to make it more attractive to the eye of the reader - same goes for illustrations and icons.

Pros/Cons

I wouldn't say she was durable in team-fights if you meant in lane then you should include that detail since from what I see you haven't gone either Atmogs or Fatamas thus making her rather squishy in team-fights even with her ultimate Transcendent Blades healing. Also, I wouldn't include being dependent on a certain lane a weakness, you wouldn't say that Tryndamere, Vayne or Morgana have a con in being able to shine brightest in a certain lane would you?

Runes

I'd include other possible runes besides these that you use for people who wish to gain a wider view of whats at hand such as Greater Glyph of Scaling Magic Resist for these wishing to be less fragile.

Masteries

I don't really see the goal behind about going Arcane Knowledge , it would be far more beneficial going Alacrity and then Weapon Expertise . Same goes for going down the utility tree to be frank Irelia doesn't gain as much from it then she would from the defense tree getting talents such as: Initiator , Resistance , Hardiness , Veteran's Scars , Juggernaut etc. These talents aid to become a true off-tank or tank.

Items

If your planning to build Randuin's Omen then you should buy Heart of Gold much earlier sometime early-game in order to fully benefit from the gold per 5 attribute (so that it will pay itself off in 27.5mins). Youmuu's Ghostblade from an end-game perspective isn't really a best in-slot item particularly for what it costs in comparison to lets say Guardian Angel, Force of Nature, Atma's Impaler, Warmog's Armor etc. I'd make sure to give these items a worth mention and Ninja Tabi if the occasion calls for it (dangerous ADs).