Then upgrading it to Warmog's after completing a few core items viable on an ADC?

Everyone is stacking warmog's, and I've been thinking. If you can't beat em, join em?

My primary answer is pending on your situation.

Health is a good thing this isn't new - it benefits everyone. If you can live longer you can either do more damage or secure more objectives, support more etc. Health helps. Even on ADCs.

I don't think you'd want to rush it as your FIRST item though - as you said after grabbing some Cores first theeeeeen I'd say it's more viable. Or earlier on if you're in a massive lead, I'm talking SK putting down the Puppies massive lead.