In fact, we are able to perform "clause counting". The total number of satisfied clauses for all remaining truth assignments is proportional to the expected number of satisfied clauses for a random truth assignment, which is the sum of the probabilities $P(C_i | \{x, y, ...\})$, where $C_i$ is the $i$-th clause, and $\{x,y,...\}$ are the literals that have been assigned to be true. In particular, if there are three distinct literals per clause, and we are promised a satisfying truth assignment (so a variable and its negation never occur in the same clause), and a single literal $x$ has been assigned to be true, then the probability that a particular clause is satisfied by a random assignment of the remaining variables is $3/4$ if the clause contains $\neg{x}$, or $7/8$ if the clause contains neither $x$ nor $\neg{x}$, or $1$ if the clause contains ${x}$. That is,
$$P(C_i | \{x\}) = \frac{7}{8} + \frac{1}{8}n_i(x),$$
where $n_i(x) \in\{-1, 0,1\}$. So the literal picked out by "clause counting" will be the one that maximizes $\sum_{i}n_i(x)=N(x)$, where the sum is over all clauses, and $N(x)$ is the (net) number of occurrences of the literal $x$ in the entire formula.
To use this to construct a counterexample, we need a literal that is false (say) in all satisfying assignments, but that maximizes the above count. We can force a literal to be false with four occurrences of its negation, as follows:
$$
\begin{eqnarray}
\neg{a} &\equiv& \neg{a} \wedge (b \vee \neg{b}) \wedge (c \vee \neg{c}) \\
&\equiv& (\neg{a} \vee b \vee c) \wedge (\neg{a} \vee b \vee \neg{c}) \wedge (\neg{a} \vee \neg{b} \vee c) \wedge (\neg{a} \vee \neg{b} \vee \neg{c}) \\
&\equiv& \Phi(\neg{a};b,c),
\end{eqnarray}
$$
for any additional literals $b$ and $c$; this subformula has $N(a)=-4$ and $N(b)=N(c)=0$. We then need to include enough occurrences of $a$ in the rest of the formula to make $N(a)$ the largest count. This can be done using
$$
\Omega(a;d,f) \equiv (a \vee d \vee f) \wedge (a \vee d \vee \neg{f}) \wedge (a \vee \neg{d} \vee f),
$$
which is equivalent to $a \vee (d \wedge f)$, and has $N(a)=3$ and $N(d)=N(f)=1$. So a counterexample with four variables and ten (unique) clauses is
$$
\Phi(\neg{a}; x_1, x_2) \wedge \Omega(a; x_1, x_3) \wedge \Omega(a; x_2, x_3),
$$
which has $N(a)=2$ and $N(x_1)=N(x_2)=N(x_3)=1$, and a unique satisfying assignment: $\{\neg{a}, x_1, x_2, x_3\}$.
