The main problems with Summon Elemental were that a) it wasn’t broken into circles, and b) it was presented as a fact of the nature of all elementals. Thus meaning summoning the Kukla was a valid summon (granted, one likely to get the entire Aerial Legion siced on you before you finished the dozens of required stopgap summons first).
I always played Summon Elemental as de facto slavery of Elementals. Not all elementals could be summoned, only those that heaven had pressed into Indenture as a form of punishment; usually inflicted by censors and Sidereals on “rogue elementals” around Creation that were breaking The Mandate of Heaven. That is, they were supposed to be criminals abusing their powers and status to control mortals and extort worship and other bullshit, but in practice this was often used as a way of bullying elementals into being Heaven’s underclass and slaves-in-all-but-name. The fact most censors were Lesser Elemental Dragons was just icing on the cake, playing off the idea of people enslaving their cousins in order to enrich themselves (look up some of the stuff in how the Transatlantic Slave Trade worked; sobering stuff, that).
Your status, or lack thereof, as summonable was maintained by The Bureau of Destiny which was also supposed to track abuses of the system. It also explains why the Dragonblooded are always summoning Elementals rather than demons, because the Bronze Faction gives them wider latitude and uses stuff like their ability to put your file into the Summoning List as a way of forcing them to accept the Immaculate Order. It also tended to push Celestials into summoning demons, since such activity was specifically not reviewed by Heaven.
I also had higher tier Summon Elemental spells, for those elementals who had transcended to Elemental Dragons at Celestial Level. Rumors persisted of Solars having access to Greater Elemental Dragons at the adamant circle, which everyone in Heaven denies but those records are sealed by Saturn and Jupiter so no one is quite sure of that. Summoning Elemental Dragons is less about slavery than it is about being attached to the Heavenly Bureaucracy; effectively, Sidereals have the right to call a Censor in to review a case and cast judgement. They’re not supposed to bind such Censors and force them to render judgement a certain way. Of course, no complaints from any Censors regarding maltreatment can be proven… or at least pinned on a specific Sidereal. Some censors and elemental dragons are unsummonable, as their missions are more permanent and valuable. Especially since it is rumored Lunars use this power to extract valuable intel about Heaven (and the Wyld Hunt) from some dragons they summon (any suggestion that such summoned censors are not being bound before being forced to disclose secrets is a base accusation that will result in an audit).
Of course, what most spirits don’t think about is that if demons and elementals can be summoned and bound by sorcery… why not gods? Why not indeed? Cecelyne would know the truth of that. Go ask her.