It's my least favorite in the series as the items are very ugly (most of them) and very limited for an AC game, and a switch game at that.
NL had nearly 3000 more items and not just color variations.
It has amazing potential though.
At launch, New Leaf had about 360 more furniture items, and that's counting the color variations in NH as one item. (NL had 1,271 furniture items, plus the 20 fossil models. Welcome Amiibo added an additional 493 furniture items. NH has 1,069 unique furniture items, some of which were PWPs in NL, and that number does include the bug and fish models, bringing the number to an estimated 360 item difference). This is also comparing a game that had all holiday furniture in the game at launch, vs one where we know items are added in patches; the Bunny Day items weren't in the game at launch, but were added in the first patch. It's reasonable to assume that this will be the case with future holiday furniture as well.
NH has 131 rugs + 171 flooring. NL launched with 119 types of flooring, WA added 42, and had no rugs. (The breakdown in NH could be off by a couple, if I miscounted. There was no easy way in VillagerDB to sort them, but regardless, NH has more flooring and a new category of flooring absent in NL.)
At launch, New Leaf had 125 types of wallpaper. Welcome Amiibo added 26. New Horizons has 247 wallpaper options. NH has 96 more types of wallpaper than NL did *after* WA came out.
I did not compare clothing, as the revamp of clothing makes it difficult to compare apples to apples. Now there is one camo tee in seven colors that is cataloged as one item. In NL, there was an arctic camo tee, a jungle camo tee, and a desert camo tee, three unique catalog items.
I don't know where you're getting this number of NL having 3000 more items.