I agree with most of that too. The reason behind me saying no champ club will get promoted is. The funding and cap is too big to bridge the gap. Also the teams that are most likely to end up in the bottom four will outbid a champ club for a player if they see him as a threat to their Top tier status. Ie just say an ageing sinfield becomes available for champ clubs and they offer say 60k for his services a team like wakey will say wait a minute he could be a threat to our survival we will offer him 70k etc. the salary cap and funding will stop the champ clubs competing IMO.
I actually think we may see a small amount of movement between the leagues. Not a great deal but a little maybe 1 or 2 in the first 5 years, the massively contrived system and wicked wango card (for the Friends fans) masquerading as the million pound game that isnt for a million pounds (its for more, why are we underselling it?) ensures a pretty small amount of movement . The problem will arise for those clubs not in the season they are promoted but the year after.
Any lower league club will have to over spend to reach the £1m Salary Cap, they will also likely need to overpay a couple of bigger names to get them in to SL. They will then start at a huge disadvantage the next year scrambling around for the scraps after the best talent has been signed up as promoted clubs have always had to.
They will also need to pay players a bit more as 'risk money' due to the fact they are quite likely to go back down and the new signings lose their contracts.
This will leave the promoted club in a position where their market for players is smaller, they are less attractive and have to pay more, and also a shorter amount of time in which to prepare as well as the need to reward the players who got them promoted with SL wages as they are now SL players.
So the club signs all these players just to try and be competitive with everyone else, loses an awful lot of games, probably makes a loss in its first season up (an almost universal result) then drops back in to the bottom 8. If that club is then relegated again it will need to shed about £900k of its salary cap have a lot less funding for the rest of their costs, whilst still trying to be competitive with not only teams spending that £900k but with other championship sides playing championship players championship wages that is going to absolutely destroy a club.
even though there is more funding, a Yo-yoing in this system is not only more likely, but more damaging.