The card is pretty effective in epic mode and other special situations. A second problem with a card like this is that if any tweaks are made to it, it could go from "not very useful" to VERY overpowered with just a small tweak. For example, putting all your beasts into attack mode is an instant win. Paying 14 for a card that makes you instantly win is overpowered. Paying 14 for a card that makes you win if the opponent doesn't have double AoE or Calamity or Mass Death...isn't completely useless like people are saying.
The only thing making this card not competitive is that its' extremely high risk / extremely high reward. It's a concept that is not good in a competitive format because you need higher percentage, low risk cards for competition. High reward/Low Risk at this time would generally be low cost characters and damage/removal spells.
TLDR - It's a situational card. Cards should be allowed to be situational.
A gimmick card shouldn't have the current level of rarity as epic. Right now it would be unusable except for just fun decks where you might get enjoyment from just pulling off a combo rather than actually winning.
You have a higher chance of winning with a deck based around Call of the Warpath (Epic Card) then you do Shrine of Victory (Epic Card). They are just situational win conditions. Only reason you see shrine more is because zero risk / minimal reward is better than extremely high risk / extremely high reward =)
Speaking of Epic cards not being useful....lets list the epic cards...1-4 being not very viable
, 5-7 being somewhat viable
, 8+ being competitive-usefulDark Wish (9/10)
Demon of Glottony (5/10)
Dragon of Wisdom (4/10)
Shrine of Victory (2/10)
The Calamity (10/10)
Aberrion, the Hammer of Dawn (4/10)
Dragon of Summer Flame (2/10)
Mega Unit 01 (3/10)
The Dragon Project (4/10)
Call the Warpath (2/10)
Hidden by Clouds (3/10)
Patient Zero (4/10)
As you can see, Epic cards are there mostly for the "fun factor" as they do ridiculously game changing things. The issue is that if a card was extremely powerful JUST BECAUSE IT WERE EPIC, then the power would solely lie with whoever had the epic cards.
I like how they generally made the epic cards into game-changers but didn't make them all overpowered.