Adric is our highest scoring Doctor's Companion to partner with a Doctor like The War Doctor
When opponents are at fewer than 40 cards remaining in their libraries, you can use the lifegain to kill them really easily
Now, your typical Magic elitist player and collector will always say it is better to brew your own, but I dont know anymore
With this knowledge it is best to play the Mana Leak earlier where possible and sensible
And I do think averaging one card drawn per turn is a realistic assumption, but again, it depends on your playgroup
But as a card most at home in the sideboard, Negates mana efficiency is perfect for combo or control match-ups when you need additional stack interaction, and when noncreature spells are exactly what you want to answer