I think the picture will be a lot different to what it looks like now, the top sides will still be a challenge but i don't think they will be as dominant as they've been over the last five years or so, SL for a start will be in big trouble as most of their batting order will be retired and Hereth may be gone aswell which would further weaken an average bowling attack,
What happens to India is anyones guess, Tendy will soon leave a hole and in four years Sewag and Gambir may be gone aswell, and currently there doesn't seem to be any great pace prospects emerging for them either,
NZ's attack will be more mature and that will serve them well, but that batting order may be a mixed bag, Williamson, Brenden and Taylor should still be decent but who backs them up? that could be the difference between them being an average side or a top five side,
Pakistan may have back the best bowling prospect i've seen in the last ten years (Ammir) in their team which would be a huge bonus of course, but their batting order will be shook up by the loss of Huq, Khan and maybe Hafeez, Ajmal and Rehman will most likely be gone too,
As for my own team, Gayle and Chanders will be a loss but Powell and Darren Bravo will be in their mid 20s by then and nearing their peaks, also expect Brathwaite to be back in the fold and there's a few batting prospects coming through the high performance centre that we're excited about, like Kyle Hope for example, in the bowling department we've got Roach who could reach Steyn levels if he carries on doing what he done this year, Narine will be more mature, Jason Holder will have stepped up (could be the next Ambrose) and Gabriel will be playing more aswell,
All sides will lose good players and have to somewhat rebuild so it should be exciting to watch and i think it will give the lower ranked sides a chance to sneak up those rankings to be honest.