Make Steraks/Titanic scale off bonus HP
Naturally bonus hp ratios would have to be higher than current max hp ratios. The goal would be to maintain their effectiveness on champions that build 2 - 3+ health items while making them far less appealing to squishies who should build lifesteal items for survivability/damage as intended.
EDIT: Another solution I saw that I like for steraks is to put a 3k health requirement to have the passive, similar to warmog's heart. Would be way simpler than trying to get the numbers right on bonus hp ratios too. Titanic hydra would still be an issue but it's unclear how hard the AD nerfs will affect it so the steraks change would be a good start.
Is most likely the best example of this. He has suffered some major nerfs and doesnt need his items nerfed too.