Nintendo: ditch Amiibo and move away from DLC, season passes, and any kind of micro-transactions in general. Bring in more talent and trust them to make games without micromanaging them. Make meaningful partnerships with third-party studios but don't waste a lot of money and resources competing with high-end tech on the market. PLAN AHEAD. Take advantage of dormant IPs, either by developing new games internally or farming them out to trustworthy independent studios. Create hardware with an attractive price point. If you must embrace a gimmick, pick one that 1) doesn't break the bank and that 2) opens up new, attractive gameplay possibilities.
Sony: end the online multiplayer paywall. Move away from cinematic action games. Go back in time and don't close Liverpool. Invest in more modestly-powered hardware. Tell us what the hell happened with The Last Guardian. Fix those sticks on the DualShock 4. Throw Vita owners a bone. Give us backward compatibility.
Microsoft: if Microsoft actually wants to remain in the console space, then it can do a number of things. End the online multiplayer paywall. Backward compatibility is great - stay the course. Build up more internal studios with competent developers. Ditch 343 and give Halo to a better studio. Don't kill Fable. Invite in more RPG developers, or build some in house. Stop wasting money buying exclusive/timed third-party content. Make more of your games exclusive. Invest in more modestly-powered hardware. Do something good with the mountain of Rare IPs you own.