They are still too weak compared to old edition deities. 2e only had rules for avatars, true deities was above game rules and 3.5e have a lot of nasty abilities to deities. Like immunity to any weapon bellow +5 and the possibility to cast antimagical field which doesn't affect the God himself while he can cast disjunction on the party and make all of his epic gear mundane and spells worthless. Not mentioning that due all energy from his followers, they allways roll the best possible result for everything. And even if you somehow managed to make then lose a lot of HP, they can teleport to their divine realm where they are near omnipotent and are protected by ludicrous powerful followers.
This talking about a general deity. Good lucky resisting an single wail of the Banshee from an deity like Myrkul... IDK his stats but believe that the DC to resits... Assuming 30 INT and divine rank = 16 (lowest of an greater deity), his DC would probably be > 10 + 10 ( int ) + 16 (divine rank ) + 3 (he probably has at least epic spell focus necromancy) + 9 (spell level) = 48. The FORT save of an CR 19 ancient red dragon on 3.5e is 22, so if the ancient red dragon rolls 19, he only gets 41 vs the 48 of this ultra low estimate..
But not even Gods, archdevils like Mephistopheles on 3.5e had a lot of nasty DC 30+ spells to resist.
NOTE : Fort save on 3.5e can be translated to CON save on 5e.
Without the help of another God, is near impossible to kill an God, even with a 12 party sized on epic level.
Tiamat on 5e is weaker than most non deity ancient dragons dragons on 2e...
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Really? One of my biggest complaints for the 5e monster manual is how few hitpoints everything has relative to the amount of damage players do
A level 10 party can kill most CR10 monsters in a single round. A level 9 hexblade sharpshooter can do over 100 damage with a single arrow
CR are too "inflated" on 5e. Monsters who are CR 10 should probably be CR 6 or 7 in other editions. And you rarely fight a single creature alone. You generally fight at least a squad of 5+.
And you are looking with only to the damage with high rolls and crits.
Did you played BG2? 3 horrid Wilting in a chain contingency can be cast in a instant and the 3 would deal 60d8 damage in a huge area, yes, 3*20d8 ( https://baldursgate.fandom.com/wiki/Abi-Dalzim%27s_Horrid_Wilting ). On 5e, it deals only 12d8 necrotic damage. Which means that the AVERAGE 20d8 damage from 2e(90) is almost the same of the max damage of the 5e spell(96)
