If it was a standalone competition that was properly sponsored and there was a decent prize money on offer, it would be taken seriously. Plus there could be a rule about how many first team players had to be included.

I think there are two reasons why the MW has been left as a standalone game and not integrated in to the post-split part of the season, one is to give the top 4 an extra home game as you have mentioned and the other is so they can sort the fixture list out early. Leaving it until the leagues of 12 are finished would mean fans would not know who they were playing or on what days until the very last minute. This way it can be sorted out months in advance. So I can see why they have kept it as it is but creating a league system with one additional fixture isn't great. I like the MW as a concept but it needs a better purpose IMO.

I still don't understand why another Cup Competition isn't introduced.
Something else for clubs to play for.
I'd love to see the Lancashire and Yorkshire Cups return to the game.
A stipulation whereby each team could only select a maximum of 10 first team squad members and the remaining players would come from the Junior team.
Would be great for development of the young lads, but would still provide enough experience in there to attract the fans.

I agree though I wouldn't do the Lancs & Yorks cups. I'd have a League cup like football where it's only the pro league clubs that take part. And I'd have all the clubs from SL, Championship, C1 in from the start.
I'd also have, like you say, either a max limit of so many first team players or a minimum of so many young players for each SL team.

So after a prelim round to get it down to 32 teams it'd be a straight knock-out comp.