Wizards of the Coast did try to compensate for this by increasing the Mana tax as you increase Esper Sentinels power, but any Auras or buff spells after often reserved for the Commander in Voltron style decks
Other creature tutors worth considering include Green Sun's Zenith , which allows you to search your library for a green creature with converted mana cost X or less and put it onto the battlefield, and Chord of Calling , which allows you to search your library for a creature card with converted mana cost X or less and put it onto the battlefield
however, Wizards figured out that the ability to consistently destroy all lands in play on turn four might be a little too powerful
The second leans into the Princess keyword and provides a great foundation to build on if you want to go more into a Princess-focused strategy
So Common cards and Uncommon contain more vanilla cards (with no rules text) or cards with just one keyword, up to 5 or 6 ink cost at max
It also works alongside Urza, Lord High Artificer and other cards that want loads of cheap artifacts