If your opponent doesn't have removal, it becomes a headache to deal with as you will be prevented from your life total reaching zero, and require your opponents to win through other means
A sudden explosion rocks the Great Illuminary
Ziatora, the Incinerator might be interested in flinging this turtle around, too
If, while you control Spider-Verse, you also control more than one legendary non-Spider permanent and at least one legendary Spider permanent all with the same name, the legend rule applies to only the non-Spider permanents
Decks that were already strong could now beat you in a whole range of new ways without ever having to tap out for more than a three mana-creature, and once that creature was on the table it felt like it both dramatically slowed your ability to attack and made the situation worse on a continual basis as every turn that went by meant another card (or often cards) available to the opponent to make Dr
You lose out on indestructible, trading it for a +1/+1 counter and hexproof until end of turn