Commentators seem muddled about why Paul describes his revelation using third person singular narration (2 Cor 12:2-5), and why he mentions that the revelation was "before 14 years". I believe that Paul does these things to show that he is, and was, reluctant to boast of his revelations.
Rival apostles were gaining the loyalty of the Corinthians by boasting (2 Cor 10:12, 17; 11:12-13). Paul therefore wrote to win the Corinthians back. To do this, he had to stoop to the level of the super-apostles by indulging in some boasting himself, but he did so with great reluctance, distancing himself from the boasting as he did it. Thus he repeatedly described his boasting as foolishness:
I wish you would bear with me in a little foolishness. Do bear with me! I feel a divine jealousy for you, ... (2 Cor 12:1-2)
What I am saying in regard to this boastful confidence, I am saying not with the Lord's authority, but as a fool; since many boast according to human standards, I will also boast. (2 Cor 11:17-18)
But whatever anyone dares to boast of - I am speaking as a fool - I also dare to boast of that. (2 Cor 11:21)
I am talking like a madman (2 Cor 11:23)
I have been a fool! You forced me to it. (2 Cor 12:11)It is likely that the super-apostles had boasted about visions and revelations and that the Corinthians had compared Paul unfavorably with them. The Corinthians would have assumed that Paul had not received many revelations because he had not told them about them. Paul then needed to show the Corinthians that he had indeed received powerful revelations that he had not previously told them about. But how could he do this without, by example, endorsing the same inappropriate boasting for which he condemned the super-apostles? This dilemma explains Paul's approach in 2 Cor 12:1-5.
Paul frames his discussion of his revelation by further emphasizing his reluctance to boast:
It is necessary to boast; nothing is to be gained by it, but I will go on to visions and revelations of the Lord. (2 Cor 12:1)
On behalf of such a one I will boast, but on my own behalf I will not boast, ... (2 Cor 12:5)He also demonstrated to the Corinthians that he was reluctant to talk about the revelation:
was caught up into Paradise and heard things that are not to be told, that no mortal is permitted to repeat. (2 Cor 12:4)and he may here be contrasting his own modest reticence with the unrestrained boasting of the "super-apostles".
Paul's use of third person narrative
Paul's purpose of showing his reluctance to boast is also served by his use the the third person. By transferring the story from himself to "a man in Christ", Paul makes his account sound much less boastful and by this means he expresses his disapproval of direct boasting. That this is the reason for his use of the third person is demonstrated by 2 Cor 12:5 where he virtually says as much.
Luke too uses the "modest third person", as I argued here.
The significance of "14 years" in 2 Cor 12:2
The revelation that Paul chooses to cite as an example is not mentioned elsewhere either by Paul or by Luke and its content could not be repeated (2 Cor 12:4). This suggests that Paul did not often talk about this revelation and I suggest that he had not breathed a word about it to the Corinthians during his visit(s) to them. Paul's decision to cite this particular revelation and to mention its date now become clear when we consider the chronology. Paul had visited the Corinthians in 50-51, some 5 or 6 years before the time of writing. It would therefore have been immediately obvious to the Corinthians that Paul had received his revelation well before his 18 month visit to them and that he had kept a modest silence about it throughout that time. Paul's mention of the "14 years" therefore serves to show the Corinthians that they should not conclude that Paul did not receive revelations from Paul's silence about them. By mentioning the 14 years Paul is contrasting his own modest silence about the revelation with his rivals' boasting. I think this point about the relative chronology of the revelation and Paul's first visit to Corinth may be new, as I have not seen it in the commentaries.
Paul could have written, "I have received greater revelations than the super-apostles, but, unlike them, I don't talk about them", but such a boast would have negated itself and would have been against Paul's principles (2 Cor 12:6b). The subtle mention of the 14 years allows the Corinthians to come to the same conclusion on their own, without Paul having to spell it out to them.
Some think that Paul refers to the revelation of 14 years ago because it was his most recent major revelation, and they infer that he had few revelations. Thus Barrett p 308: "So Paul must go back fourteen years ... for a suitable example of visions and revelations of the Lord. He was thus ordinarily anything but a visionary ...". This thinking is flawed. Paul mentions this revelation precisely because he received it well before his long stay in Corinth (and because he had not previously mentioned it to the Corinthians).
It seems to me that 2 Cor 12:2 lends a little support to the chronology of Acts. The text fits Paul's purposes best if he had spent several months in Corinth within the previous 9 years or so. Only then would the Corinthians have realized instantly (without counting years) that Paul had been with them for a long time without breathing a word about his earlier revelation. The 18 month stay of Acts 18:11, five or six years before the time of 2 Corinthians, works nicely.