Well there are flying bricks in terms of lack of greeble detail, like this:
In these cases, the hideousness is usually due to being new to the whole concept of designing ships and/or 3d modelling.
These are the newbies of the ship design world - they should be encouraged and given advice on how to improve.
Then there are flying bricks like this:
http://www.maj.com/gallery/Corhellion/R ... 2_0000.jpg
(NGTM1R you might remember this from HLP)
Though this particular example is not well greebled, there are others like it that are. Here the ship is
intended to be that simple for stupid reasons, such as: 'good gun coverage', 'solid', 'simple to manufacture', 'all subsystems are on the inside under the armour', 'no places fighters can hide', 'no vulnrable non-armour sections' and similar crappy excuses.
These are the 'n00bs' of the ship design world, where the authors will usually ignore or lash out at any form of objection or criticism, ignorant of the distance by which they are missing the point. The overall aim of any ship design is eyecandy to create a 'feel' or 'personality' for a ship, and this takes preceedence over functionality almost every time.
Occasionally there are interesting enough backstories to ships that the personality requires simplicity, like with the borg or the whale probe from star trek, and to be honest the only thing in these cases that makes it kinda ok is the mystery surrounding them in conjunction with their huge scale.