In Commander, the ability may not be powerful enough to make much of a difference, but in draft, for example, it is a reasonably good ability
Simply type in your commander and you can see popular combos that work with your deck, like the famous combo with Phyrexian AltarPhyrexian Altar and GravecrawlerGravecrawler: However your deck is planning to win, you'll want at least seven cards that provide the answer to that critical question
And I think even Randy's learned his lesson about blue
And anything else that would have happened during your draw step (like Sylvan Library triggering) won't happen
Discount HP or MP copies appropriately
Cards like these are weak against aggressive decks, but if the game goes long, Endless Ranks of the Dead generates overwhelming value