The reason Toxic Deluge and Farewell is tier 1 is because they've been printed in precons. This goes back to how stupid it is to lump all precons together and in effect state that "these are all equivalently powerful"; As anyone who attends events and shops at an LGS that stocks commander precons, you can quickly recognise that this is patently false, due to one or two precons from most releases being out of stock before release, and any additional stock they get in disappears immediately due to bookings, while the others from the same release stack up and collect dust on the shelves by the dozen. They really need to get that sorted, if they aim to have a system that isn't entirely inconsistent. Or perhaps they don't judge by power, but by "jealousy factor"? Then it makes sense. Most precon cards are, at most, 5 dollars, with a few outliers. The really expensive shit never gets printed in precons, because Wizards hoards reprint equity with the fervor of a paranoid psychotic.
i think We already had a Power system, and that was a Okay but ineffective system, due to consistency, i dont think the tier system will Be much better
To quote Joey from the EDHReCast - "It's just the same system with a new hat." And just like the old system, it skirts around the actual issue: That people, for whatever reason, are bad at doing pregame discussions and/or advocating for their own experience.