I think it is too late to add that kind of "trick" as "everyone" is switching to DoH and DoT and that makes this impossible.
And of course a lookup of *.example.net to obtain the addresses for the list is impossible.
DoH maybe a trend. almost device/software start to support it, but not default enable at all now.
I think this feature can useful a long time
@pe1chl let me explain why you are right and the OP request is real nonsense!!!
If some wildcard are used, just one "dot" for example, RouterOS, for do what you want, must try all valid DNS characters like:
1.google.it, 2.google.it .... a.google.it, b.google.it ... y.google.it, z.google.it
then with one single wildcard characters must do 40 DNS requests.
If added something like "*" wildcard, RouterOS must try from
1.google.it
to
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.google.it
for do that, must do (243 positions with 40 possible values each position = 40^253 =) ~ 2*10^405 of DNS querys
Just 2*10^405 of DNS querys, for each wildcard DNS on address list..
Numbers of atoms on the universe are like 10^82...
very feasable, not?
So I find DNS cache or listen DNS reply. I think that is better than brute force.