I am not following what you are saying. If you are not alerted of a raid while in the PVP area, how does that interrupt the game? I understand if using a scent because of being on the map, you are alerted of a request when in that part of the game as a banner. But when in PVP, from what I remember, there is no banner or alert beyond the alliance button on the bottom right showing a notification. You are only alerted onscreen if you go to the friends tab (it shows in line at the top) or to the map (it shows as a banner at the top). In the PVP area, you would only see a notification over the alliance button correct? Unless something has changed and there is now an alert within the PVP area, this is not justification in my opinion to force people to raid on certain days over having multiple opportunities to do so.
If a player does not want to raid on the weekend, they would not have to. If the constraint for someone to raid Mortem is that they need to raid with specific people, then they would need to raid at the times those people can raid. Its up to the players to decide when that occurs even as it is now. Its just broken into hours of the day instead of multiple days and hours as it would be with multiple repeat days. Because some people would raid more on the first day is not a valid reason in my opinion to say a repeat would not be good. Those players could simply not raid while the repeat would still allow those finding it hard to raid during the current times a chance to raid. There is no condition that on a repeat day someone would be required to raid.
I believe you are saying its problematic to get requests and that is the main concern here. I do not think requests would matter if you were doing a tournament because they are not intrusive in that part of the game. When outside of that area, refuse the invites like it is now on the raid days. To me saying that would be a hassle or something disregards the hassle it is for many people to do the raids on the current days because of work or other reasons. Multiple raid days would make it easier for more people.
A button to suppress raid invites though would be nice.