I think that the degree of tension/dread/excitement (delete as appropriate) in a game with randomised outcomes is directly related to how significant the outcome of an action might be.
Definitely. If win/loose has immediate impact each roll becomes tense.
I wouldn't also ommit the visual presentation. I think bringing camera to 3rd person in XCOMs, and having you wonder if you will hit or not, with satisfying zoom on kill controbutes to this effect. Honestly, I don't remember missing much in DoS2. Most of the hits tended to be guaranteed to hit, with armor being the main gameplay mechanic. Luckily, DnD doesn't do that.
