I haven't seen (and I read) for what you can change Randuin's Omen for.
In my opinion you'd be better to change it for Banshee's Veil. However, when you do a build, guide, for any champions, you need to take into consideration that readers won't necessary read it all, since gamers like me are lazy.

What I just tried to say in my earlier post is to help you figure how people understand your build/guide. Here's my advices. Try, instead of adding thousand of items in same build to do 2 builds, according to different situation. My second advice would be to details the item orders, since it's a costy build, it would be nice to explain how you get the cash, since you are the tank you want your carries to be fed before you.

My third advice would be to revise a bit the formatting of the guide, if you truly wish it to not be downvoted. E.G. try to show the items like this : Atma's Impaler, with 2 brackets (open and closed, like this: ). It adds good formatting and people tends to will to read more carefully, since it is easier for them.

I recommend you jhoijhoi tutorial (on Mobafire) about doing a guide, truly well explained and you can freely use the templates she gives. It helps a lot if you do not want to bother too much doing it.

Regards,
trIAlexCS

so what do you exchange to get the randuins?

As i said in the summary if you bothered to read it all. The randuin's is the situational item and the force of nature can be rushed depending on how dangerous the ap champions are. The boots don't have to be removed at all and i even said that it depends on the situation

Then Annie, LeBlanc, or any little fed AP Carry comes and destroy you OR Trundle destroy you with his ultrimate, stealing you 25% of your armor + Last Whisper. Seriously the lack of boots is also meh.

You have, including the boots deleted by Mobafire automaticly, 7 items, so is why your build can't work. This build is only situationnal to teams that have only ADs or 4 ADs + 1 AP or something around this compo, which never happens in ranked.

BOOTS SHOULD NEVER BE SITUATIONAL, NEVER, NEVER, NEVER, NEVER. Oh wait, never, especially Mercury's Treads