Another reason I'd say absolutely not to this is that it will put pressure on couples who don't want dad to stay. If it becomes okay, it will quickly become the norm and then expected that dad will stay all the time....
How's that supposed to help? Both parents knackered from the start, more pressure to hand off older siblings for days.
The single breathing about the time I was in hospital after DD was born was being able to hand her off to DH during visiting hours so I could rest, knowing he'd had a good night's sleep and was clearheaded and functional. If he'd been allowed to stay, he'd never have been able to make himself leave - how many times have men who don't want to be at the birth been called selfish and pathetic on here? - and then we'd both have been knackered.
And, no, I wouldn't have been happy with other people's partners staying, and I, too, think there's too much other visiting. Left to me it would be one person at a time allowed on the ward during the day and a day room would be provided for all other visiting. If mum and/or baby aren't well enough to go to the day room, they aren't well enough for crowds.
Other people's visitors were hellish when I was in. Loud, rude and selfish, and there's just no need. Other wards have number restrictions, so should maternity!