The thing you'd give up vs. a 2-bath is compensating effect. DK-25R diluted 1+1 ought to give results very similar to D-23 1+1, which means no differential in development effect between shadow and highlight areas due to local exhaustion. You'd need to dilute a lot more than that to get that effect from a single solution developer, and then there'd be the question of inconsistent or uneven development due to too little active developer for the film area (i.e. at 1+2 you'd have to increase the amount of working solution beyond just that needed to cover 35 mm film).