The translators are not likely to have made an attempt to water down the meaning here so much as to merely translate the grammar correctly.
The Greek word used in John 2:10 is in the Greek aorist subjunctive passive form. When we say in English "he is drunk", we are using the word "drunk" as an adjective, not as a verb, and it is clearly synonymous with being intoxicated. But that is not the form of the grammar used here, and the translators would not have been translating correctly to convert the Greek verb to an English adjective.
As it is, because of the difficulty of translating the Greek word, it has resulted in a longer expression in English. Verbs in Greek, like in Latin languages, can include the pronominal subject (pronoun), the action itself, the time of the action, the tense/mood of the action, and even the object of the verb--all in one word.
G3184 μεθυσθῶσιν (methysthōsin) [V-ASP-3P]
Can be broken down into the following grammar:
- Aorist verb
- Subjunctive tense
- Passive voice (coupled with "to be"; e.g. "have been")
- Third-person plural (they)
Aorist is difficult to translate to English because English does not have aorist verbs. It is a form of past tense used in narrative in which the verb does not indicate any specific time nor state of completion. Since English does not have this, however, the translators have used a past-perfect (including "to have") in the translation as perhaps the nearest equivalent.
Subjunctive is also difficult. English does not have a subjunctive verb form, and uses past tense verbs to express subjunctive meanings. A common example is "if I were you, I would...." The "were" is the English subjunctive verb. In this case, we use subjunctive because this is the unreal condition--I am not you and could never be you.
The Greek verb, however, does not mean "intoxicated" (an adjective), because it addresses an action. In order to become intoxicated with wine, one must first drink it. The action is the drinking. And English uses "drink" as a common euphemism for imbibing alcoholic beverages.
If I say "he drinks every day after work," an English speaker would assume, in the absence of any context to the contrary, that he is drinking alcohol, not water or milk or tea or juice or anything else. In other words, when "drink" is used as an intransitive verb in English, alcohol is generally assumed. To specify something other than alcohol, the object must be provided (transitive verb); e.g. "he drinks water every day after work."
So the translators are actually doing their best at properly translating both the meaning and the grammar of this passage in John 2:10, and any misunderstanding of it may be the part of the reader. Because the context of the drinking is clearly referring to wine at the wedding, there is little excuse for thinking of anything other than inebriation.
This is the reason it is always helpful to study the original languages or to use dictionaries and lexicons to help understand the meanings of the words and expressions used.