No, it doesn't seem strange to me to consider representing what I want by a bounded utility function. It seems strange to consider representing what I want by a utility function that converges exponentially fast towards its bound.

I'll repeat something I said in another comment:

You might say it's a suboptimal outcome even though it's a good one, but to make that claim it seems to me you have to do an actual expected-utility calculation. And we know what that expected-utility calculation says: it says that the resource allocation you're objecting to is, in fact, the optimal one.

Or you might say it's a suboptimal outcome because you just know that this allocation is bad, or something. Which amounts to saying that actually you know what the utility function should be and it isn't the one the analysis assumes.

I have some sympathy with that last option. A utility function that not only is bounded but converges exponentially fast towards its bound feels pretty counterintuitive. It's not a big surprise, surely, if such a counterintuitive choice of utility function yields wrong-looking resource allocations?

(Remark 1: the above is a comment that remarks that the optimum is the optimum but is visibly not missing the point by failing to appreciate that we might be constructing a utility function and trying to make it do good-looking things, rather than approximating a utility function we already have.)

(Remark 2: I think I can imagine situations in which we might consider making the relationship between chocolate and utility converge very fast -- in fact, taking "chocolate" literally rather than metaphorically might yield such a situation. But in those situations, I also think the results you get from your exponentially-converging utility function aren't obviously unreasonable.)