IMO ICC should remove the Test Status with being a full member of ICC. Also the teams should not be forced to play Test Cricket against all full members. If Aus wants to play test only with England, India, South Africa, SL, WI, NZ then be it that way, but as a compromise to it it will have to host teams like BD, Zim, Ire, Afg, Neth against Aus A. However if Aus still wants to host BD for a Test Match (If both boards mutually agree) then they can definitely go ahead. It is mutual and not forced upon
Then teams like BD, Zim, Ireland, Afghanistan, Neth, Ken, Can, Scot, Nam, UAE can play Tests Amongst themselves as part of tours and also play 5 day games against A teams of Big 8. When a performance of a Team say Afghanistan starts coming good against the major 8, then the teams would definitely like to play against them.
This way the best format of the game would be preserved and there is a realistic chance that better teams have a chance to play tests and the Associate Team can also aspire to reach there.