event venue multiple issues

Several issues with event issues, in approximate priority order:

If a new venue is added with same venue name, it fails to be added but there is no clear indication of this (after clicking submit on the add window, the window remains open, but it gives no indications of error, but it fails to add or update the venue)
If there is name conflict, it should do something quite clear and reasonable.

There should be means to correct/update venue entries - at present it only allows adding a new venue and it only gets added if it has a new name. This is very annoying/problematic/inconvenient if, e.g. venue is same business (e.g. one specific restaurant), but the business has moved location, or there are other relevant bits (e.g. comments) about the venue that should be updated - shouldn't have to give the venue a different name just to update/correct it.

Venue entry/selection is presently not user-efficient nor scalable. One should be able to:
flag entries as obsolete (e.g. business location was used as venue in past, but business has since closed),
entries then flagged as obsolete then, at least by default, wouldn't show among available selections or searches (but
would still exist so they could show in, for example, past events)
be able to pick/select/search among existing venue entries, e.g. by location, name, etc. and be able to pick/select much more efficiently (e.g. not have a list which grows indefinitely and is mostly presented in an order that is not intuitive, cannot be searched and at least for most browsers cannot even generally search for strings in the list presented, but only match by start of string)
when selecting existing venues, it should be clear and easy to distinguish and see their details (one shouldn't need to first pick it, save it, then review it to see if it's the correct one or has the correct details),