In my opinion that looks great, and there are several of other goodlooking armours to mix-match with each other, (fx: snow bear armour with stalrhim left pauldron, gaunlet, and shield)...
Another good reason to have mix-match armour is if they had made a few kinds of armour like Bonemold in Morrowind, several different styles of the same type, allowing for amazing customation within the individual sets.
A likely BS reason for the armour combining is that it allows for more NPC's on the screen: For as others have pointed out if this was really an issue than my PS3 would crash whenever I brought two trolls and five bandits into town and tried to gather ever npc there by hitting 'em and running... if this was really a that bad issue I am certain Bethesda would have waited 'till nextgen of consoles came out... and besides how can an extra armour slot (with the exact same amount of verticles as it would have if combined) really add that much more? (I ain't that knowledgable about this but it really doesn't make sense to me.
Another crappy reason for the greave-cuirass merge is that "most cuirass cover most of the legs." I mean seriously? so what if I'm just wearing a shirt, or if I'm not wearing a shirt I'll be forced into underwear...
and that even would make more sence merging boots than cuirass? (which I'm also against) I mean then I'd atleast be able to not wear a shirt but still have pants.
And the final reason was that it allowed for more freedom to the designer... which neither merging pauldrons 'nor greaves do, Seen that elven armour? this one: http://www.elderscrolls.com/skyrim/media/screenshots/cave/ you can even see that its a vest underneath those clavicles, if seperated the designer would simply have to finish the vest, and then once you equip pauldrons the clavicles would go ontop... I doupt even Daedric armour would stick out so much that it would go through the clavicles, after all there is no reason to make it thicker as both are plate... sure they'd have to make it less spicky at the top... which according to this concept art: http://dl.dropbox.com/u/8613775/Skyrim/LedererPics/DaedricArmor.jpg is infact only part of the pauldrons.
And this is infact the only (slightly) proper reason for the merge.
EDIT: And people please try to keep a civil discution.
EDIT: And when quoting whole long posts like mine, please remove the text (makes it alot more nice scrolling through.