Board Thread:Warhammer 40k General Discussion/@comment-24037808-20140924094901/@comment-6078851-20140925140551

the main point for the breakdown of the legions was so that no single commander could command a body of troops large enough to threaten the imperium, as horus did. as much as i would like to see a reformation of the legions of old, in all honesty such vast formations of super-troops is insane overkill: astartes are the best of the best ... of the best. it makes far more sense, tactically, to have such troops grouped in smaller numbers - as is mentioned the imperial gaurd do the bulk of the fighting while astartes are for surgical strikes or exceptionally dangerous enemies.

and even after the legions were reduced to a thousand per chapter they can still pose a significant threat in taking over star systems, for example huron's rebellion.

in regards to the thing about tight bonds between chapters, almost no-one trusts the dark angels. the only chapters that are actually happy to work with them are their own successors as they all share the burden of their past.