>>>> 1) Option or command to automatically go to the other end on exit.
>>> 
>>> It seems the conclusion was that it should not be an option. As for a 
>>> command, there were objections against binding it to a key, but 
>>> without a keybinding such command has little sense.
>> 
>> I attach a patch which implements these two "options" in isearch-exit.
>
> And of course my patch had an error ;-)
>

While we're improving isearch, there is another minor change that I think 
would improve its behavior, namely to go to the next/previous match when 
changing the search direction, instead of hitting the same match before 
moving to the next/previous one with the next C-s/C-r.  This change is so 
small that I'm not sure it's worth creating a defcustom for it, but you 
might have a different opinion.