So Yi is a potato in 14.10 but this is an off-meta tank build that seems to make him fairly useful.

Your goal is to focus on Health, and take health+damage items. You play pretty much the same but you can support the team very differently and play much riskier. Starting fights is fine with this build, and you can recover health very fast - especially if you opt for Warmog.

Depending on the situational items you take, your playstyle will diverge. If you take Heartsteel for example, you're going to be looking for dives that get you the most procs, in and out. If you're up against a tank heavy comp you're going to want Cleaver and to stay in fights longer. Up against crit you're going to want to hard commit back-lines with Randiuns.

That's basically it, just flex on the items and change your play style to adapt.