Other reply was pretty long, and this is disconnected enough to warrant its own.
Recursive spells- or, recursive runes - would only ever be as complex as the enemies or level. As I have no reference for what other work may have been done on this game, I can only consider recursive spells (in this environment) to be of low utility. The bigger problem is that they would not act like functions. Spellcraft currently has effects and objects to apply these too (or in refence of, in the case of the x, y terms). It is currently missing the third category: effects to apply too. Or, what I would call Meta spells/meta runes. Meta spells would be effects that only applied to magic and, in my opinion, would fix a large hole (?) Spellcraft currently has. For example, a Mirror meta rune that can hold x mana (costing the player x mana plus the cost of the rune to cast initially) which, when activated, casts its own spell (using its given mana) composed of every rune preceding it (in the same front-back order), but in the opposite 'targeting' direction. This one meta rune already presents multiple different applications. 1) Preforming a 180 degree spin (assuming a metarune exists for that, or it is keyed to the character orientation) and a short delay before casting the mirror metarune would have it hit the desired target 2) Literal Raycasting. A beam of death (through arbitrary means) which uses the mirror metarune so it can count as an aoe attack. 3) Combat blink: A short range teleport with a delayed mirror metarune would be great for dodging. 4) would achieve multitargeting with certain set ups.