Here are the facts as I think the organization saw/sees them:
(1) To be competitive in the NHL, you need to be strong down the middle. Backstrom's demise and Kuznetsov's implosion decimated the center corps. The Caps had no replacements, and won't have for at least a few years. You can only get top NHL centers at the very top of the draft, or through draft luck you can't foresee. Where the Caps have drafted for the most part, you can't get anyone that you can even be moderately sure could be a top-6 C. In this year's draft for example, the Caps have pick 17, and if they are lucky might be able to get Michael Hage, who has promise but is far, far from a sure thing to be a top 6 forward.
(2) Kuemper was a waste, and a mid-30's waste at that.
(3) Nobody is going to trade the franchise or near-franchise centers without warts. So how were the Caps going to try to improve themselves at center ice? The only real other option, if one wants talent, is to acquire talent with warts, UNLESS a top-flight center hits UFA.
The nice thing about this trade is that it addresses all of (1) - (3) above with one move, and a move that gives up nothing we didn't want to give up. I don't know the FA and trade market this summer. Is there any really premium center (Dubois tools or better, without the warts), that the Caps could possibly acquire, and if there is, would we have had to break the bank to get that person, either with money as a UFA or players/prospects/draft choices in a trade?
Then there is the elephant in the room: Ovie for his last two seasons to try to break the scoring record. He needs a center to work with. I wouldn't be surprised if Dubois comes to camp with the expectation that he will be Ovie's center.