True, I would rush philosophers first with boots then rush my core, the regen is excellent for in between ganks and the gold for when not in a lane, quite priceless. However, I don't follow this strategy currently.
Doran's is simply not something I am recommending. Upon reviewal that has not changed. 2 slots to attempt to outbenefit one slot of item of which the outbenefit is questionable? I assume this is sarcasm. I recommend what i think should be kept. Exceptions being intermediary items like the 5 gold per 10 sec series. Anything else i view as a waste of money or... slot space.
Legion use is explicit. Grant yourself and nearby allies some survivability. I think the thread is about what to do if your lacking survivability and thus it isn't plausible to go strictly a fixed core and extensions. I assumed a scenario could be your team (not necessarily simply you) lacks survivability and and this occurs to your team's detriment inspite of you being the initiator. Thus you don't need to improve your defense so much so as your team's. This item improves your team and your character more such that should they decide to focus you you've still improved your defense.