It's something we have thought about before, but we kind of see it as a workaround. While it is an improvement, it doesn't solve the core issue. That being said, if we can't solve the core issue, then obviously this is the next best thing.
One other concern is what will it end up looking like if everyone on the server has this enabled, and everything is always auto-extended. I think it's not hard to see that this will have an impact on how long each map is played, which can be good for players running the maps, but not always great when people want to play new/other maps. So things like whether this would be a permanent or temporary setting, and who has access, will need to be considered.
It's interesting results on the poll so far with a reasonably even split between those that do mind and don't mind the weapon switching issue.
Poll