Blackwood is for Squares?

K Q 7
Q J 6 4 2
K J 6 5
2
2 10 6
A 10 9 8 7 5
A 10 9 8 4 7 3
Q J 10 8 7 4 A K 9 5
A J 9 8 5 4 3
K 3
Q 2 Opening lead: A of diamonds
6 3 Vul: Both

WestNorthEastSouth
Pass 1 Pass 1
2 2 3 4
Pass 6 Pass Pass
Dbl All pass
Last fall, I recall offering a similiar situation asking rhetorically, "Blackwood is for sissies?", drawing on the title of Art Linkletter's book, "Old Age is not for Sissies." Of course, there are times when you want go directly to a slam rather than futz around with Blackwood. One reason for doing so is because you know you want to be in six (you've got first round control in three suits and second in the fourth and little slam strength has already been indicated -- why go to Blackwood as a formality when you might give the opponents to make a lead-directing double?). Another reason might be that four no would be ambiguous -- your partner bid no trump a while back and no suit has been agreed upon -- and you can't afford to give your partner a chance to pass short of slam. Nevertheless, if you're not bidding on a point-count of 33 and do not have the necessary controls in your own hand, Blackwood (or maybe Gerber) is certainly indicated. It's not sophisticated to jump to slam, particularly when you're off three aces! The times Blackwood allows the defense to make a devastating lead-directing double will be offset 10 times, twenty times, by the times you're missing two aces and can recover in a five bid. And then the leapers have egg on their face.
Here the declaring side is missing three aces and kind of misjudged their strength, not to mention the number of controls. Blackwood wouldn't have spared them from going down, but it would have saved a trick -- and would have made the declaring side look a little more savvy.
[years later]Of course I shouldn't be advocating Blackwood when it's the presumption of slam potential that's glaringly at fault. North opens with an absolute minimum opening bid -- some might even say sub-minimum -- and offers a classic case of bidding the same values twice. His two diamond bid isn't forced, with that 2 club bid on his right, though actually I wouldn't quibble with it. However, at that point, he's finished, that is, for any unforced bid. He's bid all his values and then some. South's leap to 4 spades announces just that, that South thinks they have a reasonable shot at game in spades and he shouldn't be punished for that very reasonable bid by being yanked two levels higher. The fact that North has better support than South could reasonably count on doesn't cut any ice here. Rather it should make North feel comfortable that he can offer that fit, not evidence that he can go two tricks higher. The K and Q of spades were already bid with North's opening bid.
Oh, but can't the opposition make 5 clubs, and didn't we pre-empt them out of that with a good sac? Yes, it would appear they can make five clubs and no, that's not a good sac. North clearly didn't bid to sac. And if it's a sacrifice he wants to claim, well those guys didn't bid five clubs, and if they did, five spades would be a worthy sac. Now if they go to six, whack 'em.