I'll express my opinions about every item that needs to be changed visually. Overall, the new displays are great and I was excited to see the changes made. However, I don't think that every single items needed a remake over, and generally, just the ones that did not have a colorful background to complement the item itself. Here is the list of icons I didn't like:

Single Items

Blades of Alacrity - Emphasis on the blades
Blink Dagger - Old looks great
Claymore - Old looks great (new is too dull)
Cloak - Old looks great (same with Claymore)
Demon Edge - Old looks great
Eagle Horn - Both looks amazing, but I prefer the old as it represents a brighter color
Energy, Vitality, Point Booster - I don't understand why you would redesign the three perfected items into dull, colorless looking pieces
Gauntlets of Strength - Old just needs a background color, not a dull re-make
Gem - Same with Gauntlets, just needs a background color, and the new looks terrible, unfit to represent the theme of Dota 2
Gloves of Haste - The old one looks better as an icon
Mithril Hammer - I personally prefer the old one, but both looks standard
Mystic Staff - The old one looks amazing enough
Reaper - The old one looks good enough
Smoke of Deceit - Old one looks better

Recipe Items

Drums of Endurance - Add the background color to old and that's your answer
Sange & Yasha - I disagree with the neon green color choice, it's terrible on two sets of swords
Satanic - The old one looks a lot better
Eye of Skadi - The old one looks better
Shiva's Guard - The old one looks better, again the new icon is dulled and lost its magic
Divine Rapier - The new one doesn't represent the word 'divine' at all. I think keeping the old one is a good choice
Mjollnir - The old one preferred, without question
Daedalus - I think everyone would agree that the old icon looks amazing enough
Heart of Tarasque - The old one just needs a background color
Magic Stick - The old one looks so much better
Mask of Madness - The old one looks good enough, but the new one can be implemented with some background color added
Desolator - Old looks great (too much going on in the new one)
Diffusal Blade - Same problem with Claymore & Cloak, the old one looks terrific
Bloodstone - Old looks great
Butterfly - Old looks great (the new one also looks good, but it is too polished)
Battlefury - Old looks exquisite and a lot better than the slanted axe (new)

This list is in no particular order, and I hope it helps in the adjustment that's going to be made to the Shop Visuals that will make Dota 2 an even better game.