Another interesting suggestion!
Concerning hero promotions: In view of Saga2 (Re: All heroes are low-capped at Rank-3), I think the optimal play of Saga1 is to actually try to promote as few as possible while hoarding Renown... I usually focused on promoting only the lead "unkillable" heroes (Rook/Alette, Iver, Oddleif, Hakon) in my games, which left many of the others to serve bench roles. Moreover, with how the turn-order works, it's often better to bring fewer & stronger heroes in a battle, rather than field low-rank/injured guys.