I wouldn't mind the next game going back to MW and showing us the aftermath of the Reaper threat. I would also like Shep to be alive as i really wasn't a fan of Ryder. Have the game take place maybe a year or two later when everybody is rebuilding and then hit them with another threat.
Not anything universal like the Reapers, but maybe some other alien faction looking to capitalize on the situation since everybody is vulnerable during this rebuilding phase. Andromeda going 300 years into the future was a bad copout by Bioware not wanting to deal with the aftermath and dealing with a true canon of ME3.
Just pick a canon ending (most likely destroy with Shep living) and run with that....there was no way Bioware was going to satisfy everybody....so just take your own personal journey with Shep and treasure it, but just accept what canon ending the devs choose to roll with and respect it.....Bioware backed themselves into a corner with that 300 years into the future garbage...