[ywl]

I think the strategy is abusive and would like to see the exploit removed.

But I have the suspicion that the effects you saw was because of high research and large gem income, rather than specifically because of Tartarian Gate. It doesn't seem to be too much more powerful than some other strategies, if you could get to level 9 on Conjurations or Construction and have the right gem income.

Examples:
1) Tarrasque. 25 Nature a piece. In my test, most tartarian zombie needs GoR. So, the gem cost is about the same.
2) Juggernaut. 25 Astral. They're powerful tramplers, holy and can spread your dominion.
3) Heck, if you have GoR, you could even use it on Gargoyle. Use Vanheim and a Nature 3 pretender. Research for Enchantment 5 and high Construction (4 or 6). GoR the Gargoyle and pile items on them. They'll be quite decent combatants, though their basic MR is just 12.

Of course, most Tartarian summons are powerful magic Users. Your strategy still has an significant advantage over these three examples, even though it's harder to pull of.

What bug me more is actually seeing an whole army of dead gods running around. Does it make sense to have tens of imprisoned ancient gods available for summon? Personally, I'd rather see all of the Tartarian summons unique like the Demons, and the cost of the spell and chance of feeble-mind decreased to increase their power.