Lastly, I'll emphasise on the witty dialogues. The playing on the phrase "way of the world", as discussed before, is itself a great wit. Besides, the proviso scene is a wonderful example of wit. The powerful ending and the humorous epilogue are also ironic with a moral in them. And, not the dialogues are only witty; as it is a comedy of manners, the playwright distinguishes between pseudo intelligence and true wit. For that reason, a clear contrasting border prevails between the characters of Sir Wilfull Witwood, Witwood and Petulant who are examples of false wit, and Mirabell who is the model of true wit. (Reference: Introduction of "The Way of the World, edited by Kajal Sengupta")
Now, I think, this answer would help you to some extents regarding your question.
The Answer I would like to give dividing into two parts as it is quite long to encompass it within one post.
A Restoration comedy is a form of comedy which flourished during the Restoration in England (1660-1700). According to M. H. Abrams -
It deals with the relations and intrigues of men and women living in a sophisticated upper-class society, and relies for comic effect in large part on the wit and sparkle of the dialogue - often in the form of repartee, a witty conversational give and take which constitutes a verbal fencing match - and to a lesser degree, on the violations of social standards and decorum...
Actually, the common features are: witty dialogue, intrigues in the plot, and most importantly satirizing of that contemporary Restoration upper-class social system. The way of the Word is an excellent example of Restoration comedy, since it contains all the above characteristics.
In The Way of the World, the phrase "the way of the world" has been recurrently used, for example, Fainall first uses it in Act 2 : "the Ways of Wedlock and this World", and repeats in the third act : "all in the Way of the World" and also in the final act, And at the end Mirabell's mocking approach: "'tis the Way of the World, Sir; of the Widows of the World". This repetitive motif makes it clear that the play is concerned with the problems of the social system. Marwood and Fainall are those who eavesdrop, blackmail and play intrigues. Both Fainall and his wife pretend to be very nice with each other, though, both know that each is wearing a facade. Marwood and Fainall use each other for their own sake. Millamant feels comfortable when she is surrounded with men, though, she is aware of the fact that the men are simply foolish. Lady Wishfort's sole desire is to hold on youth and beauty. Millamant does not forget to bargain with Mirabell before accepting her proposal in the proviso scene. Thus, Marwood's eavesdropping and blackmailing, Lady Wishfort's continuous attempt to make herself look younger, or Millamant's staying surrounded by fools and bargaining, and, Mrs. Fainall's being deceived by Mirabell - all these express feminine vulnaribility in that contemporary society. The falsehood in a marital relationship is depicted nicely through the Fainall couples. In fact the aristocratic men in the Restoration society would do nothing but playing cards and drinking chocolates, which are justly portrayed in The Way of the World. So, undoubtedly, Congreve's play is a wonderful social satire in the face of a witty comedy. In the epilogue, you will find these ironic lines quite a satiric evidence of this: "Tho' they're on no Pretence for Judgement fit/ But that they have been Damned for Want of Wit."
The intrigue, in the plot, is a significant theme, and has been used as a tool to satirize the degradation and follies in the social and individual behaviors. This intrigue is best expressed via the hide-and-seek between the Fainalls. Both the husband and the wife lack love, faith and adjustment. They hate each other, get involved in extra-marital affair, yet, both pretend to be extremely loving to each other in front of others. Fainall bears his marital life since his sole concern is his wife's money. And, this is the money which makes Marwood play love-game with Fainall. Mirabell, too, plays with innocent Wishfort to get her niece. So, all are planning and scheming against one another for their own sake.