For a single illustration, it's fine to have super-detailed characters! If the artist feels it's going to take them substantially longer, they can simply charge more. Most artists will have a clause like that in their terms and conditions.
But for a comic, simple designs are far better. Otherwise, it'd take forever to complete an episode. You can still have excellent character design while keeping things comic/animation friendly. Look at TV shows like She-Ra, Avatar, Voltron, and so-on. They all have excellent character designs, while ensuring that they're not so over-complex as to double the animation time. My character designs in Blue Star Rebellion have been complemented a lot - it's one of the most frequent I get - and they're also very simple. Hell if I'm drawing two-dozen buckles and belts on a character, when I have to draw the character 20 times in a single episode.
The trick with making simple characters memorable is good shape design, strong colour theory for their base colours, and unique outfits which suit the character's personality. If you're looking for that, you should specifically seek out artists with strong character design skills in their portfolio for the initial character sheet, even if they cost a little extra.