Melosia + HA Tokens + Lingbao's Will allows for 1 huge swing, but thats honestly more of a problem with Lingbao's will breaking all interesting morale-based cards, and Heaven's Assistance being a pretty stupid token generator card.
Equilibrium is an excellent control card and is an example of some interesting mechanics we are seeing being introduced into Overseers, where they are very much a 'jack of all trades' aggro faction with decent battle control tools. When you say it ''makes no sense for Oversers to have this card'', may I ask what you are basing what ''Overseers should have'' on?
Also, Forerunner of the Champions is honestly a fine card, the command zone that takes advantage of it is highly beatable. The thing is that it might require some adjustments to existing deck lists in order to react, but I can list off many outs that factions have currently to this command zone. If a command zone is counterable, has interesting counterplay, and is overall interactive, then I think it is a good thing to have.
I will say that the mana curve for some factions could use some further fleshing out (WP and Exiles having few low drops, FD needing a bit more of a late game that isnt calamity or fear/ferocity combos, CoV needing a few more characters), but overall I think that the current game is evolved enough to where Tempus + Forerunner commands are fine. The deck is powerful, the deck is good, but it is a healthy deck, and it is balanced. I raised the same concerns back during beta testing of the set, I thought it's damage output was absolutely outrageous, but the tools oppression has introduce render it a lot less threatening. If you threw Tempus/Forerunner commands into Order's meta, it would be incredibly strong, but Tempus and Forerunner were not the only cards introduced this set. 3 DoD vs 3 OoS match up (which used to be hilariously in OoS favor) is now extremely interesting due to Gao Han Stalwart's popularity, Lance of Jinhai, and other interesting tools the faction has gotten, along with Overseers getting Equilibrium, which can definitely mess up a DoD player's day.
I think Oppression has introduced more soft counters, more interesting match ups, and is a lot more skill based then the last meta, and most older players agree with this assessment. The only exception to this is Counting the Days which nearly everyone hates with the blinding fury of 1000 suns.
But overall, the direction of Overseers is quite interesting with all the different utility cards it has. You can run Life Gain/Burn 2 Ex 1 OoS, you can run Burn 2 OoS/1Fd, 2 Fd/1 OoS, Aggro 2 Oos/1Cov, 1 OoS/2 Cov control, 2 DoD/1OoS defense, 2 OoS/1DoD morale decks, 2 OoS/1DoD defense decks, 3 OoS, 2 OoS/SoA, 2 Gi/1OoS Aggro, 2 OoS/1 Gi 'Bio Sol', all of which are of varying levels of power, and above all, many of them are extremely, extremely interesting and fun to play, and above all, fair.
Heaven's Assistence, Box of Wonder, and Higher Calling are honestly the only cards in the OoS purity which might need some adjustments, everything else is quite frankly balanced and fair.