Banning both is a severe over-reaction. It's still allowed to be a T1 deck, and since mana ramping is still a legit strategy and considering Tron lands are allowed, Temple remaining would be just fine. What can't be allowed is infinite, scalable mana ramping that allows for free spell casting on T1. Eye is the problem.
With only Temple, Spreading Seas/Molten Rain strategies would actually be viable. Without Eye, Thought-Knots couldn't always come down before reasonable counter strategies, Mimics couldn't come down for free, Displacers couldn't cost one and repeatable tutors couldn't be a thing.
Temple still allow T1 Mimic T2 TKS T3 Smasher. Eye don't. Eye is legendary and terrible in multiples. Triple Mimic T1 is not that good when you can't follow it up with TKS or anything bigger than a 3/2. I agree the effect is stronger in a vacuum, but i think the deck would actually be unplayable (with some good starts) with just eye and actually decent with just temple.
EDIT: also i agree that they should actually ban everything that is over 50$ so the game is actually affordable and scalpers can go fuck themselves.