I don't think it can be as impressive, as SF is really better than QF : to reach QF, you only meet players ranked 13 and more if you're ranked in the top-4 like Fed.
And 23 SFs in a row is really huge
The second one for QF has 27 of them : Connors, who didn't play the Australian open and sometimes couldn't play Roland-Garros then did it on a longer period of time, which makes it all the more impressive
Whereas for SF, the second one after Fed is also Connors but with ... only 11 semifinals, which means less than half of Fed's.
Anyway, for me, the most impressive from Fed was the 18 finals in 19 grand slams