I am going to link this thread to the beta testers and apocalypse mod team, and have them discuss the balance of SOB in THB 1.79.8 as current and tell you in their opinion how SOB are in terms of balance.

If it were from me, I really have not seen an Arch Angel upgrade 1 go up against two Hierophants and one Hierophant can take on two reavers and more if they get within range of melee when they are clumped up. Difference being, don't pit a Reaver versus a melee titan. The melee titan needs to get in melee first without being taken out by many other sorts of units in range first. Titans weakness is melee combat. So it will be fair, especially when you have those 5-6 reavers.

I was attempting to make allowances for real-life game conditions when I said 1-2, which means the likely possibility that one of the hierophants is significantly damaged. 

In addition, my objection to the current archangel has nothing to do with the fact that ranged titans don't handle melee titans well (I only used reavers as an example, and I specifically stated different numbers for ranged and melee titans)-it has everything to do with the fact that a single unupgraded archangel is superior to all other titans 1v1 (except manta which it can't hit b/c melee can't hit flying), while a 1 or 2 upgraded archangel is superior to everything including manta, which it can just ignore most of the time.

Furthermore, I don't think you were paying full attention to my post; I stated that it is mathematically impossible to have 5-6 reaver titans in a standard 4v4 game-there is no map that has enough relics for everyone, and even if they did, maxed relic research only gives you 10 relic points.  At most, you can have 1 reaver and 1 warhound per team, assuming they each have one relic and maxed research.

It also doesn't help that all the ranged titans are slower than cold molasses and extremely unwieldy in movement-unless all of them are lucky, and I stress lucky, enough to confront the archangel in the same spot at the same time, you aren't getting any of these ideal matchups where they might attack it all at the same time.

Arch angel can be easily defeated by chapter master(upgraded), besides, SOB doesn't have any ranged titan so it gives an advantage to other races, if it's about balancing imperial guard have way more firepower, basilisk magnus can annihilate almost any squad with one hit, and a Primarch angron can defeat 2 Arch angels at once but the ability "divine slaughter" is a big advantage, although arch angel can be easily spawned since it doesn't need much of resource, but it takes somewhat faith to fully upgraded, and I've been doing a lot of tests, And what's really annoying is that Repentina veterans an defeat any other squad including grey knight paladins and terminators, I think a morale increase for the grey knights would be good.