That's a bloody tough question to answer.
I think, like Sandy, I'll need to have two answers based on sentimental and aspirational.
Sentimentally I'd like to fish with my Dad again. He's quite infirm now and, whilst he lives just yards from some of the best water on the Deveron, he'll never fish it again - nor is it likely he'll even manage part of a day at Artloch again. Missed opportunities.... when you think you have the time to do these things again, you don't
Aspirational list is crazy. Immediately names like Skues, Oglesby, Currie, JJ Mann, Hemingway, Eric Clapton, Paul Whitehouse and so on. Each with their 'USP' which intrigues me to know what a day afloat or on a river with them would be like. Coming down to one person is tough, really tough.
I think it would have to be Charles Ritz who did, to my mind at least, have an incredible influence on rod and line design, was a formidable fisher, fishing adventurer and scribe.
H