There were certain recognized openings for decorative effect. Boileau advises the epic poet to be 'vif et presse' in his narrative passages, but to let himself go on the descriptions:
Soyez riche et pompeux dans vos descriptions:
C'est là qu'il faut des vers étaler l'élégance.
For an English poet, being 'riche et pompeux' usually meant writing in the style of Milton, and that meant writing in blank verse. Johnson certainly expressed the normal opinion about blank verse when he asserted that it could only support itself with the help of rhetorical devices.
'If blank verse be not tumid and gorgeous, it is crippled prose' (Lives, ii. 319 f.).
It is no answer to Johnson to cite Lear's
Pray, do not mock me:
I am a very foolish fond old man,
Fourscore and upward; not an hour more nor less...
or the fine close of Wordsworth's 'Michael':
Among the rocks
He went, and still looked up to sun and cloud,
And listened to the wind...
No one has ever doubted that there can be short passages of entire simplicity in blank verse. The problem, however, remains: can blank verse on a consistently subdued level be tolerated all the way through a play or a long poem? Even in his 'Michael' Wordsworth was sometimes driven to the sort of heightening that Johnson had in mind; e.g. 11. 110 ff. in which he describes the cottage chimney 'with huge and black projection overbrowed', where hung a lamp, 'an aged utensil', the 'surviving comrade of uncounted hours'.