“Tacky” is a cheap pejorative for things that someone doesn’t like: it disses the idea without really saying anything legitimate about what is wrong with the idea. It’s like playground name-calling: an insult with no thought behind it.
The exception, of course, is address labels 😉 The actual dictionary meaning of tacky is “Slightly adhesive or gummy to the touch; sticky,” and even the staunchest defenders of address labels cannot deny that the term applies. Of course, it also isn’t a bad thing in this case: labels wouldn’t be much use if they were NOT tacky.
Of course, if people were to think critically about why they dislike this or that idea, they might still condemn it. They would just use more descriptive — and possibly more damning — terminology. Putting your wish-list reference on what is supposed to be a generous hospitable invitation seems mercenary and materialistic; even greedy: it betrays a sense of entitlement and a willingness to take advantage of your guests’ generosity. If people really need your help in selecting something appropriate for a gift, you will come across as more gracious by insisting that you really want only their good wishes. If you can’t bring yourself to do that, leaving the gift choice up to your guests’ ingenuity is the next best choice. Not “Tacky”, but still not desirable.
Adding maps, hotel information and block booking contacts to your invitation; sending advance advertising in the form of save-the-date cards; and creating a website make your wedding seem commercialized, like a business convention. It conflicts with the social and spiritual nature of a wedding, and depersonalizes the invitation. Also not “tacky”, but not the motif most brides are going for, either.
The handwriting-on-envelope argument is pretty specious. First of all, printing instead of handwriting on the invitation envelope breaks no more “rules” than does printing instead of engraving on the invitation itself. And nearly everyone accepts printing on the invitation. They’d be pretty inconsistent to worry about the envelope, which is after all just the wrapper for the invitation, when they’ve accepted the compromise of printing on the part that matters. And secondly, the reason given for handwriting the envelopes is that it shows “personal attention”. Anyone who has ever set up a mail-merge to print envelopes and then fed the finicky odd-sized envelopes through the blasted printer, knows that there is a great deal of personal attention being used in that exercise, too. I have gorgeous hand-writing and love using it, but even I resort to printed envelopes when the guest list approaches its second hundred.
R.s.v.p. cards with no stamps? I hate them — but I hate them with stamps on them, too. I find it bossy and presumptuous for a hostess to try to dictate what stationery I should use to reply to her invitation. If it’s easier for your guests to phone, text or email, then why not just graciously accept their responses in whatever manner they choose to send them? Being gracious to your guests is never “tacky”.