I've been thinking about the Epicureans and their conception of virtue. Here is the text of Kyria Doxa 5 as printed in Von der Muehll’s edition:
 οὐκ ἔστιν ἡδέως ζῆν ἄνευ τοῦ φρονίμως καὶ καλῶς καὶ δικαίως <οὐδὲ φρονίμως καὶ καλῶς καὶ δικαίως> ἄνευ τοῦ ἡδέως·  ὅτῳ δὲ τοῦτο μὴ ὑπάρχει, [οὐ ζῇ φρονίμως καὶ καλῶς καὶ δικαίως ὑπαρχει] οὐκ ἔστι τοῦτον ἡδέως ζῆν.
We can divide the Saying into two parts, labelled  and  above. The first part is the less problematic both textually and philosophically. The words in angled brackets <οὐδὲ φρονίμως ... δικαίως> were supplied by Gassendi and his conjecture was confirmed by the version of the saying inscribed in the lower margin of Diogenes of Oinoanda fr. 37 Smith.
The second part of KD 5 is more difficult. The MSS reading is difficult to construe. Furthermore, the words in square brackets [οὐ ζῇ ... ὑπαρχει] do not appear in the counterpart of this saying in the Vatican Sayings (VS 5: οὐκ ἔστιν ἡδέως ζῆν ἄνευ τοῦ φρονίμως καὶ καλῶς καὶ δικαίως. ὅπου δὲ τοῦτο μὴ ὑπάρχει, οὐκ ἔστι τοῦτον ἡδέως ζῆν.); they are therefore deleted by Von der Muehll, who is followed by Marcovich. What is left behind after the delection is not very elegant.
Bailey and Usener offer attempts at reconstruction so as to produce something that adds more to the overall sense of the Saying.
Usener offers the following:
ὅτῳ δ’ ἓν τούτων μὴ ὑπάρχει οἷον ζῆν φρονίμως, καὶ καλῶς καὶ δικαίως ὑπάρχει, οὐκ ἔστι τοῦτον ἡδέως ζῆν.
His text is followed by Hicks in his Loeb edition (bar replacing οἷον ζῆν with Bignone’s ἐξ οὗ ζῆν), who translates:
Whenever any one of these is lacking, when, for instance, the man is not able to live wisely, though he lives honourably and justly, it is impossible for him to live a pleasant life.
ὅτῳ δὲ τοῦτο μὴ ὑπάρχει, οὐ ζῇ φρονίμως καὶ καλῶς καὶ δικαίως , <καὶ ὅτῳ ἐκεῖνο μὴ> ὑπάρχει οὐκ ἔστι τοῦτον ἡδέως ζῆν.
And the man who does not possess the pleasant life, is not living prudently and honourably and justly, [and the man who does not possess the virtuous life], cannot possibly be living pleasantly.
Bailey raises various grammatical difficulties for Usener’s construal. But his most serious objection is philosophical rather than philological. On Usener’s reconstruction of this part of the Saying, as is made clear in Hicks’s translation, we are offered for our consideration the possibility that someone might live honourably and justly without living wisely. Such a person is then said not to be able to live pleasantly. The possibility is not offered in counterfactual terms; rather, it is simply stated that such a life will not be pleasant, not that it would not—per impossibile—be pleasant. And such a life without phronēsis will not be pleasant even if it is a life lived honourably and justly. It therefore seems that while phronēsis might be a sufficient condition for the possession of all the other virtues, it is not a necessary condition for the possession of any or all of them. If this is right, then it is a rather striking concession on the part of the Epicureans. There are good reason to think that, at least according to the account in Ep. Men. 132, the derivation of both the virtues and a pleasant life from phronēsis makes impossible a just but unwise life. For this and other reasons, Usener’s reconstruction is unlikely to be correct.
But I wonder whether the concession that it is possible to live justly and honourably without Epicurean phronēsis is a concession that could be strategically very useful in the broader debate between the Epicureans and their critics. More when I've thought that through a bit more.