I've just noticed that archangel's price is higher than normally it should be. The worst part of it is that they cost 5000/3gems while "Castle" city type does not have proper resource silo.
In each city that have 7th level units that cost Additional Resources (gems, crystals, flour etc.) on both upgrade levels (Angels 3000 gold 1 gem, Archangels 5000 gold 3 gems), resource silo produce one unit of certain resource while in castle it provides 1 wood+1ore.
Who made a change in Archangel's price and why?

And is there a chance to get a patch that provides "damaging moats"?

AA's cost so much because they are probably THE best level 7 unit in the game.

Seriously in a head to head match vs any other level 7unit they win. And this doesn't even take into account that they can resurrect allies in bigger fights.

Actually the only other T7 unit that comes close to standing toe to toe with them is actually Ancient Behemouths. This is because their special ability reduces AA's 30 Defense by 80% down to a lowly 6.

Just to clear things up: 5000g+3 gems was introduced back in SoD.
Polish gold edition had an incorrect price of 5000g - it's been fixed in one of unofficial patches. Hence there might be some confusion about AA's price.

But yeah, post SoD this price is correct.

Proper AA price is 5000 gold only (without gems) in RoE and AB. In SoD the price was intentionally changed to 5000+3G.

ofc it was because they relized that 5k alone was to cheap for such a creature.

Think about it this way. If you took 1 AA vs ANY OTHER T7 creature the AA wins. That's even vs ArcDevils who can hit without retal and hate angels and AD's cost 4.5k & 2 Mercury.

If anyone doubts I am willing to write a match between any two T7 units for you to see how good thay are.

An example of how good they are is given on the Celestial Heavens website in a Fantasy Death Match between 50 of ArcAngels and 50 ArcDevils without any Hero boosts. The first attack of the AA's kills off 20 AD's with AD's retaliating and killing 5 AA's. Even after that they then get a free hit to kill 6 more AA's on their attack. This leaves 39 AA's vs 30 AD's after just 1 round of combat.

Shadow of Death updated some stats and prices for Angels and Lizards and their respective upgrades. It also brought in the damaging moats.

So prices of units are corrected but moats are still safe places?

Moats are NOT safe places. Since Shadow of Death and also in complete and the Chronicles Moats deal damage.