I object to North's choice of 3D on this hand. The description is "4+D; 4S; 11+ total points".
First of all, it is clear that the bid is not meant to be forcing, if this hand is anything to go by. North is not a passed hand, so there should be an upper limit on strength in the description. But really my main objection is not to the description of the bid but rather the choice of bid.
GIB system is to open 1C with 3-3 or 2-3 in the minors, and to open 1D with 4-4 or 3-2 in the minors. Some of these holdings can be eliminated by the auction. South would bid 2S over 2H on pretty much any opener with 4 card Spade suit. So let us place South with at most 3 Spades. That eliminates any (balanced) opener with a doubleton in the other minor and only 3 cards in the minor opened.
It may be reasonable to assume that opener has at most 3 Hearts. In real life this is not guaranteed, and occasionally the Hearts may be 5-2-2-4 around the table despite the raise. In which case opener could theoretically be 3-4-3-3. But I don't insist on it and would be happy for GIB to conclude that South must by now have at least 4 Clubs.
Furthermore, if he also has 4 Diamonds then his Club suit must be at least a 5 card suit. Furthermore, he could well have a 5 card Club suit without the need for holding a 4 card Diamond suit.
All in all, Clubs rates to be at least as good a place to play as Diamonds. Sure, occasionally you would prefer to be in a 4-4 fit than a 5-3 fit, but it does not always provide an extra trick and the preference is overshadowed by the primary obligation to maximise your chances of playing in a fit rather than a misfit.
On a given day, 3C may not be significantly (if any) better spot than 3D. There may be no 8 card fit to be had. But in that case there will be a 7 card Spade fit to be had at a lower level
So, not that I advocate North bidding 3C, it would still have provided a long term gain over 3D.
However the simple fact remains that while South is now unlikely to have 4 card Spade support, there is nothing to prevent him having 3 card support, on which occasions it is entirely credible that Spades is as good a fit as any to be had, and has the advantage of being biddable at a lower level.
A balancing take-out double of 2H by North would have kept this option open, without closing the door on 3m should South not have 3 card Spade support.
To my mind, X by North instead of 3D is a clear winner.