Introduction: NOT boring....
In the world of album cover art, the best thing would of course be to have a great and/or iconic sleeve design for your record cover.
The art/design itself doesn't have to be great though; if the artist(s) look striking enough (Beatles, Simon & Garfunkel, Morrissey, Madonna, Adele even) then a decent plain photograph is a more than acceptable solution to the album cover issue.
Failing either of those, a truly bad sleeve may be the best option for attention-grabbing purposes. Obnoxious and Neil Young are truly dreadful, but even the contrived-ness of the Acid Reign sleeve doesn't make it any less memorable.
Arguably worse than a truly bad sleeve design is a truly bland one. ALL talent show contestants' album covers have them, most bands and artists of any standing have at least one in their discography.
Black Sabbath have covered the whole spectrum:
Black Sabbath (Vertigo, 1969) see also Sabbath Bloody Sabbath (1973), Never Say Die! (1978)
* Iconic creepy image perfectly encapsulates the tone of the music within
* Photographic/modern and yet artistic & timeless
*low-key, moody but powerful use of colour
* Excellent 60s-ish logo, never fully adopted by the band but often imitated
Born Again (Vertigo, 1983) see also Paranoid (1971)
* laughably un-scary image
* suggests artist had seen album title + band name but not heard record
* looked instantly dated
* garishly nasty use of colour
BLAND BEYOND BELIEF
Seventh Star (Vertigo, 1986) see also The Eternal Idol (1987)
* "fine", unremarkable picture of Tony Iommi
* uninspired fonts & safe colour scheme
* cheap-looking framing of central image
* how could the designer be bothered to hand this artwork in or the label be bothered to use it?
Notable examples of bland artwork abound, especially in the 80s, when pretty much every major established star of the era (McCartney, Elton John, Phil Collins, Tina Turner, Rod Stewart, Dire Straits) dealt exclusively in the kind of bland packaging most suited to their 'product', but some less obvious examples are equally unfortunate...
Anti-Pasti - Caution in the Wind (Rondelet, 1982)
Not bad artwork, but the urban grittiness of the picture itself is undermined by the strangely random pale colour washes over some areas and the jarringly out-of-place band logo. Patchy album too, so sort of fitting in a way.
Pilot - Second Flight (EMI, 1975)
The Edinburgh band's clever, classy post-glam pop never got an album cover to match the quality of the music and the lazy artwork for their second album (featuring their biggest hit January alongside lots more quality guitar-pop) is probably the BLAH-est of them all....
The Pooh Sticks - Trade Mark of Quality (Fierce Records, 1991)
Okay, so ramshackle Welsh indie isn't likely to spawn Roger Dean-esque works of art over triple-gatefold sleeves. But you'd still expect a twee, homemade, perhaps childish charm (like the Archies-inspired art on their Great White Wonder), rather than this impossibly boring-in-every-respect sleeve.
Queen - Greatest Hits (EMI, 1980)
Strange that such an image-conscious band should approve such a drab cover, but I suppose a guaranteed huge seller didn't need much attention. The 'trapped in the Phantom Zone' layout is both BO-RINGGG and dated too...
Otis Redding - History Of Otis Redding (Atlantic, 1968)
Nothing captures the emotional power of Otis Redding's brand of soul music more than a wistful B&W picture of the singer on horseback with an autumnal green border. Nice, in a way but ???.
Nazareth - Play 'n; the Game (Mountain 1976)
Nazareth are a highly underrated band, responsible for some of the best hard rock (and hard rock sleeves - see Hair of the Dog and No Mean City - of the 70s. But you wouldn't know it from the sleeve (or title) of their '76 opus.
David Bowie - Stage (RCA, 1978)
Although Bowie was in the middle of one of his best periods in '77-8, RCA seemingly tried to make this so-so live album sound as bland and unspontaneous as possible. The cover (pointlessly a gatefold) compounds the sense of 'completists only'.
Kiss - Hot in the Shade (Mercury, 1989)
Even Kiss' worst album covers (lots to choose from) usually have a kind of cheesy flamboyance; but not so the tepid Hot in the Shade, also perhaps their most yawn-inducing album of the 80s
Lou Reed - Rock and Roll Heart (Arista, 1976)
Lou Reed is responsible for some of the best (Transformer) and worst (Lou Reed Live) album covers of the 70s. But he was rarely boring. The title, cover and about half of this album are an unwelcome exception. He got much better at being boring in the 80s; witness Legendary Hearts, Mistrial, Live in Italy etc etc etc....
The Stranglers - Feline (Epic, 1983)
Pink Floyd - The Final Cut (Harvest, 1983)
Pink Floyd managed to build a formidably interesting series of album covers through the 60s & 70s - even the covers of The Wall and Dark Side of the Moon, although (to me at least) a bit dull, are iconic & memorable. The Final Cut achieves the same level of dullness without being iconic.
Genesis - Duke (Charisma, 1980)
I am not a Genesis fan, but I do think their 70s work is interesting and (usually) housed in excellent sleeves. At the turn of the 80s though, the Phil Collins-led incarnation of the band announced a new era of commercial blandness with this highly apt artwork.
...and in a class of their own....
A special case, despite being one of the great bands of the 70s/80s, Talking Heads albums rarely came in anything other than dull, uninspired sleeves. Those below are just the blandest....