Looting is good enough that you can pretty legitimately play it in any deck but it becomes really quite something when it is in those decks most full of synergies
The haste-matters decks like Minsc & Boo, Timeless Heroes and Ognis, the Dragon's Lash havent adopted it as an auto-inclusion yet, so that tells you something
Similarly, if you sacrifice a creature to activate a mana ability while activating Heirloom Epic's ability, that creature won't be on the battlefield when you pay the ability's activation cost, so you won't be able to tap that creature rather than pay one of the mana in the activation cost
You can almost feel the chill seeping through your boots
In recent years, Wizards of the Coast has been pretty consistent about doing something for Legacy (if necessary) during the midsummer while shaking up Modern in January or February
Little card upgrades you can make to improve your deck and keep up with your playgroup