Sure, the Cloak of the Undead is certainly the "strongest" artifact, but what's the point of discussing it if it just sits there and grants Lich status. It's better to discuss some original cases from gameplay where a particular artifact was used in an unusual way.
The Admiral's Hat, as the esteemed Amber wrote in PhysMig, can be used to increase movement points on land if there is water nearby.
I don't like combining Titan's Rumble — the helmet reduces strength. I prefer to put it on before a mana well/vortex, and then take it off and replace it with another hat=)
Regarding the fact that the Cloak of the Undead helps little on small maps — we all remember the first mission from the Campaigns for Sandro, where he is limited to level 5 and barely manages to get expert necromancy. That's enough to beat everyone...
As for the Father of Dragons' power — I've never combined it, even if all components are present. It takes up slots and hinders reviving. It feels uncomfortable somehow=(
Just now with Armageddon