Argument ellipsis (AE) has recently been gaining in prominence as the analytical tool employed to account for null argument data in a wide range of languages. The choice between this analysis and the null pronoun alternative is frequently determined based on two types of data, namely, a comparison of the interpretive properties of the null argument and an overt pronoun and the availability of null arguments in the absence of a linguistic antecedent. In this contribution, I look more closely at the nature of the AE-null pronoun distinction, showing first that the frequently-employed diagnostics require reconsideration. I probe into the predictions of the two analyses with respect to the behaviour of null and overt pronouns, as well as full, lexical NP arguments, focussing on two factors, that is the interpretive differences between null and overt pronouns and the conclusion that null pronouns are needed on either account. I then consider the issue of the representation of exophoric null arguments in relation to the representation of exophoric overt pronouns and exophoric ellipsis in general. As these phenomena have not been sufficiently explored in the existing literature, using exophoric null arguments as a basis in developing approaches to representing null arguments is inherently problematic. These issues lead the discussion towards considering the representation of null arguments with the language acquirer in mind, the complex picture of licensing null arguments observed both cross-linguistically and intra-linguistically potentially resulting from an interplay of different properties of the grammars of the particular languages.