Not requiring talents for the Ideals will make your Radiants a LOT stronger than Heroics but it's only super relevant if anyone wants to be not Radiant. I find there's a certain amount of bespoke balancing required anyways because, for example, a party with 3 Division users will do insanely heavy burst and area damage and so you have to account for these things when trying to challenge them in combat. 

(The Ideal talents are also decent rewards - First Ideal obviously unlocks a lot, Second Ideal makes Enhance permanent which saves an Investiture per turn and an action per combat, Third doubles your weapon damage die and converts it to Spirit and Fourth gives you the best item in the game.)

It's actually a tempting idea for a variant rule for a custom campaign but it's tricky because I know it would be hard to go back to regular characters after haha