What’s the problem with excessive citations? Citing only a single publication to prove a fact is shaky scientifically. Multiple citations are more robust in case of a dead link or if a book goes out of print or a particular version of it has the reference and others don’t.
If you’re bothered by seeing excessive citations, then the solution is to hide them, e.g. [12] (+12), and expand them on demand.
Wikipedia actually has an article about it. They are mainly bothered by the unreadability of it. Editors can indeed bundle citations as you suggest, but it takes some manual effort.
Citation overkill is also a bit of a red flag for edit wars, or barely-notable things that someone really wants to have on a wiki page.
