More effective from a logical narrative standpoint, yes.
But I was glad I got to kill one of those two in ME1, and I was pissed the other came back to haunt me and waste a roster spot in ME3.
Those scenes just weren't necessary. It's utter shit. Just show him dreaming of Reapers demolishing cities.
Oh I agree that the scenes in general were bullcrap "war is hell" nonsense and that Ash/Kaiden were awful characters in ME1 (and continued to be in ME3).
Just that, if they were going to go down the PTSD route, there was a much better alternative.