[Cohen]

I believe the actual system works just fine.

Otherwise this could be scrap the Research Priorities / Rush for uniques and this could cost much more to the victim than the 2nd summoner.

If your plan is going to use your X Elemental Ruler, with full equipment, and it disappears (even if there're little chances, but it's usually 1/4) you're losing a powerful unit, a lot of gems for equipment and probably your enemy has it.
Even this could bring to a summon-countersummon til the shortage of gems waves smiling to a player, making not so usable a unit that appears one turn, and could disappear another one.
It could be a sort of Djinn ... who usually equip the Djin if not with low cost trinkets? But Djinn is very powerful, could both trapeze and teleport iirc and has many paths in magic.