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This has been a popular question which has haunted many go fans.

I have thought over this for quite some time. I would have to say no.

Reasons

1. Pro games have shorter time interval now.
I can safely assume that most players have been influenced by the time system more or less to some extent. If you play only untimed games and try to read deep and as many lines as you can, you would eventually develop a habit to do that in all your games. Shusaku would be able to read out more lines and much deeper than any pro in our time. That alone is a huge edge.

2. There are no reigning go champion in our present time.
Even Lee Chang Ho who is considered to be the world's strongest players now has his bad days. So far, Gu Li has a decent winning rate against him.

The exception of course is Go Seigen. But he is not considered here because he has retired from official pro matches.

Possible opposing points

1. Our knowledge in the game of go is far superior than it was in Shusaku's time.
True. Extensive research and improvement has been made in the game, but most of them pertain to fusekis and josekis. It's not uncommon for a pro to win a game which he or she had an slight inferior position at the start. So it all bores down to how deep and how extensive you can calculate in the mid game to outwit your opponent.

2. Japanese professional go players have not been performing well these few years.
The reason for this might be that Chinese and Korean pros tend to be more active in researching for newer and more daring lines. But this has nothing to do with the past and never forget how Go Seigen dominated the Go world in the 50s and 60s. And also how Japan is a power to reckon with in the 80s and 90s. Who knows, Japan might make a comeback in the next decade.

On a side note, I do think Go Seigen in his prime days is the only one who might have a chance to beat Shusaku, though my bet is still on Shusaku.