He's a favorite with a lot of people, but see E. H. Carr's not entirely fair condemnation of Stephen Cohen's favorable biography of Bukharin, where Carr rejects the idea of Bukharin as a serious alternative to Stalin and Stalinism:
"'For three or four crucial years when Stalin was building up his impregnable hold over the party and the state and beating down the opposition, Bukharin was his zealous henchman.' Bukharin was no fighter, he [Carr] insisted; and Stalin never treated him as a serious rival. Granted, Bukharin was tried and executed in 1938. 'It was no act of disloyalty to Stalin on the part of Bukharin, but a paranoiac streak of almost motiveless vindictiveness, which caused Stalin to sweep him into the blood-bath of the last great purge trial.' Delivering the final blow with a backhand, he suggested that this attachment to Bukharin was to be explained by the feeble impotence of the American left:
'A second and more agreeable factor may also have been at work in Mr Cohen's assessment of Bukharin — the desire, especially strong among American liberals, to believe that nice men make good political leaders. Cynical observation may throw doubt on this conclusion. In our own century, Lloyd George and Franklin Roosevelt were superb political leaders, but not perhaps very nice men. George McGovern and Edmund Muskie are exceedingly nice people, imbued with humane ideals and unimpeachable principles. But if a biography of one or other of them fifty years hence seeks to depict his hero as a lost political leader, frustrated only by the develish machinations of the wicked Richard Nixon, he will be seriously distorting history. And this is what has happened to Mr Cohen over Bukharin...'"
https://books.google.com/books?id=bBpLFKl6X_0C&pg=PA276
Cohen replied that he had made no such claim "His thesis did not depend upon alleged political skills, but on the ideas that Bukharin had developed from Lenin's last articles: a strategy for the attainment of socialism which amounted to a 'viable programmatic alternative in the 1920s."
https://www.google.com/search?biw=1......0...1c.1.64.psy-ab..0.0.0....0.N65FC9R7WDo
Whatever one thinks of the dispute between Carr and Cohen, neither of them seems to have a very high opinion of Bukharin's "political skills."