Of course, when deciding what to use and what not to use, the question is weighing disclosure as a benefit against disclosure as a liability. However, the detail possible for super-accepts by the 2NT opener can be wildly increased, it seems.
Take the simple example of a transfer to spades. If Opener has a suit with a hole, a suit where a stiff or void from partner would be quite nice, he could bid 3NT. If Responder wants to know what suit, he bids 4♣, asking. Opener then replies, showing clubs via 4♠. Thus, 3NT would show an undisclosed Empathetic Splinter, with 4♣ asking for its location. With, for example, AQxx-xxx-AK10x-AK, Opener would bid 3NT, and Responder, if interested in the location of the hole, bids 4♣. Opener bids 4♥. After a heart transfer, 3♠ shows the undisclosed Empathetic Splinter (UES), and 3NT asks for its location, 4♥ showing the hole in hearts.
If Responder is not interested in the UES, he simply signs off.
You could even get a little more sophisticated. If Opener has the UES in the suit that can only be shown by bidding game, this deprives the partnership of LTTC. The same occurs if the UES is in the suit immediately below the agreed suit. So, if Responder has strong interest, he asks. If Responder has mild interest, where he would want to LTTC the sequence even if Opener shows the "right" stiff, then Responder shows the no-LTTC shortness. With the suit immediately below the agreed trump suit, Responder just bids the shortness with mild interest (4♥ is spades agreed or 4D if hearts agreed). With the other no-LTTC suit, Responder shows that stiff artificially by bidding the suit two below trumps. Thus, after 2NT-3♥-3NT, 4♣ asks and 4♠ responds club EP. So, Responder could instead bid 4D to show a mild slam invite with a stiff or void club. If 2NT-3D-3♠, the spade EP is shown after 3NT by bidding 4♥, depriving Responder of LTTC, so 4♣ by Responder instead of 3NT asking would show mild slam interest with a stiff or void spade.
If Opener does not have an UES, he cues normally (cuebid the lowest suit with KQ or better at the top); 3NT for spades if hearts is the focal major. The inference from the option of a UES relay is that Opener does not have a hole suit and thus must have control of all suits.
This also can get sexier. Again, we have a LTTC problem is Opener's only side suit with two top honors is the suit immediately below the agreed major. So, he bids game in the major with a mild slam interest and two top honors in the one-under suit, or bids the one-under suit with two top honors in that suit and very strong slam interest.
If you imagine that super-acceptances usually show 5 covers plus something nice, or six covers, this works rather nicely. Most top honor patterns can be described fairly well, with very little in the way of problem hands.
Consider a wildly uninteresting hand like Qxxxx-xxx-Qxxxx-void. After a 3♥ transfer, how nice would it be to hear a 3NT UES? If you are aggressive, you check back with a 4♣ call and then move past game if partner bids 4♠ to show no wasted values in clubs. If you are conservative (rational?), you take a tame position of bidding 4D to artificially show mild slam interest with shortness in clubs and trust that partner, with AK-AQ-AK will look to see if he has something else of use (3-2 in the reds with four trumps, the heart Jack, a fifth diamond suggesting the alternative strain, etc.). Amaxing how four-counts can actually be handled competently in slam probes, eh?