In what world or scenario is Dorans blade better than dorans shield?
Dorans shield provides so much more in any scenario.
If you want to play passive, shield helps you sustain a bit of poke, and grants a mild bit more hp than dorans blade.
If you're in a losing matchup, shield helps you with hp regen, and the extra hp helps against all-ins. If you're in a winning matchup, you can avoid autoing and get sustain from shield, effectively freezing lane, and putting the enemy laner further behind.
The only thing I could think of is that you can stack dorans blade, but very few champs can abuse this effectively (toplane rengar, ashe, cait, a few more), but even then ifs usually better to just build other component to a big item, like a tiamat or a pickaxe.
???