Please forgive me if this is an old topic; I'm new to the forums.
In RQ2/3, the amount of Battle/Spirit Magic a PC could learn was limited by INT. In RQG, it's limited by CHA.
In RQ2/3, the amount of Rune Magic a PC could learn was unlimited — as much POW as they chose to sacrifice. In RGQ, it's again limited by CHA.
In RQ2, Battle Magic succeeds unless the player rolls 96-00 (if I'm reading that passage correctly), and Rune Magic always works — Resistance rolls then happen as-needed. RQ3 introduced the POWx5 roll for Spirit Magic, and Divine Magic is 100-ENC. RQG kept the POWx5 for Spirit Magic and added the Rune Affinity roll for Rune Magic.
I was curious as to the rationale for these changes. Personally, I feel like spells just working and then the player dealing with Magic/Rune Point costs and Resistance rolls in enough; I don't see what's added by having them roll just to cast the spell (particularly the "double jeopardy" when they have to roll to cast and then roll again for Resistance). I also find the change from INT to CHA for Spirit Magic limits weird — it weights CHA more heavily than earlier editions.
Any insight is welcome.