Garry Sobers batting stats are ridiculously good. If Ben Stokes wants to surpass him in near future then he needs to work on his bowling. Considering his recent bowling rank (23th), i would say real hard work and if continue his batting form for the next 2 years then there is a good chance.
Being a All-rounder is tough job indeed, that's why we don't see many top-notch all rounders in intl cricket.
Garry Sobers is the benchmark when it comes to all rounders in world cricket as he was an explosive batsman and he could bowl fast and would bowl spin according to the pitch condition and he was a brilliant fielder in slips as well as in the outfield and there is only Jacques Kallis to compare to that level of skill level in the history of cricket and for Ben Stokes to reach those levels he needs to improve his catching skills as i have seen him dropping catches and need to play consistently for a longer period of time.
I doubt if Stokes going to surpass Jacques Kallis even on batting, let alone Sobers. If he's focusing on only Test/ODI then there is some chance that he could play longer and come close to them but again their Test batting average is above 55 and Stokes is still under 40 average.
He always perform in big games tho, which is commendable.
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Edit : Windies won the toss and opted to ball, Again!
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England (Playing XI): Rory Burns, Dominic Sibley, Joe Root(c), Ben Stokes, Ollie Pope, Jos Buttler(w), Chris Woakes, Dominic Bess, Jofra Archer, Stuart Broad, James Anderson
West Indies (Playing XI): Kraigg Brathwaite, John Campbell, Shai Hope, Shamarh Brooks, Roston Chase, Jermaine Blackwood, Shane Dowrich(w), Jason Holder(c), Rahkeem Cornwall, Kemar Roach, Shannon Gabriel
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Edit : Roach got the first wicket (Sibley) score is 1/1/1