I base my comment on the suggestion that the WI comprised players from various islands and that Lloyd molded them into a team. They weren't a rabble pre-Lloyd but they weren't as unified.
Yeah, I was exaggerating slightly. But I have long felt that Lloyd himself has not been slow to overstate the impact of his captaincy. From a purely English pov, Kanhai's side beat us just as comprehensively in 1973 as Lloyd's side did in 1976. And they had twice beaten us comfortably in the 1960s under Worrall and Sobers too. If anything, I'd argue that Worrall was the one who unified them. And Lloyd having his tenure coincide with the arrival of Richards, Greenidge, Roberts, Holding and the subsequent batch of quicks owed nothing to his captaincy skills. Did they become more unified under Lloyd? Maybe, but I don't really know what that means in a cricketing context.
Brearley's another one who's slightly over-rated imo. Obviously a very good captain from his time with Middlesex, but lucky to take over when he did; Willis stepping up several gears, Boycott returning, peak Botham, playing several sides who were weakened by WSC. And he never led England against WI of course. Similar to Illingworth actually. He also inherited some really good players, several key opponents could euphemistically be described as 'transitional' and never led his side against the best side in the world because they were banned. I actually rate Vaughan and Strauss ahead of Brearley and Illingworth as England captains.
I'm surprised that nobody has mentioned Benaud yet. 20 years later, Howarth and Mushtaq did brilliant jobs with NZ and Pakistan respectively. More recently, obviously Border and Taylor ahead of Waugh and Ponting. As I said previously, it's about trying to identify value added rather than win percentages when your side in full of ATG players and/or the opponents aren't all that strong.
If pushed for an answer to the thread title, I'd go for Benaud.