I was playing Risk at Conquer Club a few weeks ago, and quickly found myself feeling annoyed at the experience. At first it felt like the interface was just wrong, and I tried analyzing it from a UI design perspective, but ultimately that just didn't hold up. In terms of giving the user control and being highly responsive, the interface efficiently handles rolling dice, calculating how many armies from each side were lost, and showing you the results immediately on refreshing the page.
What I finally realized was that the dice rolls just didn't feel right. It has nothing to do with the actual math; the system is sound, using highly random source data used to generate dice rolls. But the experience of the player changes dramatically when the process of manually comparing dice rolls is automated and reported instantly. In fact, "dramatically" is exactly the word, as what was lost was the narrative and dramatic tension created by the space of time between rolling the dice and knowing the outcome. Those numbers used along the way meant something to me when I played.
A quick example: say I attack your one army with two of mine, and I roll two fives and you roll a six. I will look at my dice and interpret it as, "My armies were strong, but the defender was unstoppable!" Then I try attacking from the other side with another two armies, and roll a two and a one, with the defender rolling a three. I look down, shaking my head thinking, "Arg, my armies totally missed their chance! Those slackers!" Often that sort of interpretation even becomes part of the social enjoyment of the game, complaining bitterly out loud when the dice rolls are low and cheering when my defenders stave off a high attack roll with an even higher defense.
At Conquer Club, that entire level of representation is ignored. Sure, they display the dice rolls, but to be honest when the interface is that efficient, you tend to just look at the final results. Take the example above: the exact same mathematical scenario would've been reduced to:
*click* "Rats, I lost an army there. Let's try from the other side…" *click* "Drat, not again, another loss!"
Essentially the layers of mathematical meaning are quickly reduced to a binary win / loss, with the subtleties of the intermediate steps and their representational meanings being ignored.
Now, this is anecdotal, and maybe some of the web game's users play through slowly enough to appreciate the dice rolls. But I'm not really trying to pick on Conquer Club so much as I'm noticing it as a design consideration. It's interesting to note that the results themselves aren't the only thing that will affect your players' play experience – it's how they perceive those results, and how they came about.