an aside to this... how about anything above basic creature summoning requires a large quest/input... it has the potential to be unbalanced (as does creating artifacts)... I know MoM was fun but unbalanced from creatures and artifacts. Creatures the computer didn't pay upkeep for nor use them well and artifacts the computer didn't use at all. But even with better use, artifacts were based on skill level not research, so you could make shields of magic immunity+3, orbs of flight and phantasmal hasted bows +3 at the very start with the correct picks... the balance here was the difficulty in making the mixed artifacts such as combining magic immunity with regeneration and invulnerability... since it would require luck and questing (hoping for retorts). The replayability came from making the most of what you had, using regeneration one game, bless another, flight the next...
With creature summoning... you need to have choices, having to make the most of what you have and some way of increasing your options so you don't feel completely constrained.
Quests are one way of doing this, say you want to make custom monsters, you research adventure techs and get questing, start a quest for "find new magical monsters" and several new monsters will appear/visable/highlighted on the map, you pick which one you wish to hunt down... catch it and gain it's abilities or body plan. I talked about other ideas related to this a while back in Demon studies.
I would like for a set list of monster body types, fairy, spider... and for you to be able to add abilities to the creatures you can summon or provide large twists to their default settings... say give spiders the ability to walk on water, cast magic or make them twice the size... but not everything, there need to be factors other than just cost of summoning to consider.
One option could be giving essence to a commanding monster to be able to give it special artifacts which affect every monster of that type (including itself). The artifacts could be expensive, unique versions of things you can normally make... like an orb of healing. Or they could be special rewards for quests or defeating certain monsters. Perhaps a mix of the two, you can find an orb of fireward... or you can slay fire elementals to collect the resources required to make one. (slaying your own would be possible... but they wouldn't go down willingly). That way you can make a phantom warrior which does no damage... give essence, make a shadow sword, give him the shadow sword and now your phantom troops are able to slice up enemy archers if they are given a chance... but lose the commander and lose the bonus (and a sword that could be given to skeletons for a nasty surprise the next battle)
I still like the ideas that came up in demon studies...
I suppose the additions are that you need Choices, weaknesses, strengths, limitations and the ability to increase your power.
I'd like that non-magic versions of these could exist as well, train creatures to give them extra abilities but have training times and linked building requirements, artifacts in the training ground could enchant the creatures. Handler experience and abilities could improve controlled creatures.
Golems? choice of power, speed or health... what materials to use, abilities, support mechanic... you could choose at the start if you wanted to create living golems without support costs but requiring essence, golems with mana upkeep, controlled by a mage or idle constructs that you need to use artifacts to power.
