Well, we've passed turn 60 in the game I'm playing with EDM, so I guess I have enough of a sample size to provide some feedback.
Roc: Too expensive and not powerful enough to use in battle, I think his role is limited to mobile sieger. (And patroller when you happen to not be sieging anything.) He's less efficient gem-wise than Gate-cleavers, but without the hammer discount the difference is small, and sometimes you just have more air gems lying around. Also, you don't have to choose between using a useful unit for the sole purpose of carrying the gate cleaver, or giving it to someone expendable, who might die from an earthquake or other battlefield-wide effect. I summoned one to help with a siege, then promply lost him to an AI Niefelheim counterattack while he was flying over.
Shishi's: The cheapest teleport capable raiders you can get, and strong enough to clear out any amount of PD. Also beefy enough and capable of inficting a decent amount of damage to use as part of bigger armies. I have not seen them fare well against other thugs though, even being pounded into the dust time and again by Raksharaja's, who, as demons, should be their prefered targets. (Note that the Raksharaja's were fully kitted out though, so probaly represented a bigger gem investment than a Shishi, on top of their gold cost.)
Asynja's: I haven't seen them get much love, but I like them. (Allthough it might have something to do with being a sucker for air magic, while not really enjoying most of the heavy-air nations in the game, so any summon with air magic gets my vote.) Those with at least 1E can be used as heavy duty SC's/bruisers with all the earth and air buffs, or, alternatively, teleporting RoS casters. Possibly with the use earth boots. Those with at least one extra air pick can form the core of army-busting "Wrathful skies + a few heavy duty bruisers" squads. I see less use for those who only get blood and/or death picks, unless you need to break into blood magic. With enough boosters A/B gets you a Robe of the Magi though.
Ember Lords: In one word: Awesome. They carry a hefty price tag, but they're the kings of the battlefield. Give them earthboots (not mandatory, but recommended in many situations) and enough reinvigoration and script Phoenix Pyre, earthpower, iron will (if needed) and invulnerability (or a less fatiguing iron skin if you're not afraid of lightning.) With appropiate resists they'll survive anything.
Zmey: Not very impressed. Too expensive for chaff clearing, and while they might be able to kill a medium-level SC it's very hit and miss and they're vulnerable to SC's themselves so I wouldn't use them in an anti-sc role unless you're desperate. Mostly conjecture and watching other peaples Zmey's performances though, didn't use them myself in MP.
Firebird: No opinion for now.
Wendigo: Excellent for their price. (Which obviously take into account the wait for them to grow up.) With quickness and Soul-Vortex can do lots of damage to both strong targets or masses of troops depending on their equipment. They are somewhat vulnerable to heavy hitters though. I lost one to a Zmey, and another to Lankan Sacreds. Can also take over the Kokyatids W gem to D mage conversion role if you're not pressed for time.
Grendelkin: They look good to me on paper, but allthough I have summoned a few they haven't seen heavy action yet. They look perfectly suited to accompany armies, both to take out opposing SC's (Gloves of the Gladiator!) and as damage sink.
Kraken: Not used yet. I'll withhold judgement untill I'm ever involved in an underwater war and have to decide if I want to spend my W gems on them or something else.
Mechanical Giant: Pronounced strengths and weaknesses, and as such somewhat situational. Stay away from anyone capable of casting opposition, but useful if either you or your opponent want(s) to dominate the battlefield with the mass-elemental damage enchants. Low hit points will allways make their use risky, but they are cheap. I used mine fully equiped, (and they died, after doing some nice stuff and some sucky stuff) but am now wondering about using them as disposable thugs with minimal equipment. Early pseudo-SC for people rushing for artifacts. If MA Agarthan Dominion works as reported the hp hike takes them into true SC levels, as long as you stay away from opposition. (the spell that is)
Cyclops: I sank a ton of earth-gams into gate cleavers and even siege-golems for a remote-distance campaign, so haven't tried them yet. I haven't quite figured out what to use them for yet.
Ettin: No natural armor, no resistances, no magic, and lowish MR. They'll die to something whatever you do. 3 arms, high strength and decent attack skill seem to indicate a role of anti-SC, but they lack the teleportation to catch them on their own, and if you use them in an army they'll die whatever you do. (Possibly after killing thier target, but they will die.) Gem-sink for the unwary, stay away. (Regardless of cost decrease. Make them free, and the gems to equip them for SC-killing would probably still make them not worth it.)
Treant: As most others have said before: don't have spare nature gems, haven't used.
Re: End game diversity mod
Hybrid Mode
