Outside Kojima's game, I had a vague idea about every single game shown at E3 for the  major conferences. 

I might have to go full media blackout next year.

Knowing things in advance is a great way to keep your hype meter in check. And yes, that is a good thing.

This is actually only true for english speaking companies and developers, Japanese not so much

More or less.The new games havent been leaked though, and we had no idea.The only one we could say we saw it comming was RE 7, but even then we(well, me at least) was blown away by the trailer and finally it being(aparentally) a survival horror again.

I'm sorry a few trailers were spoiled for you.

But we still dont know what happened to Thief 4 and why it was such a mess, and what went wrong with the development of games that were announced a decade ago like Final Fantasy 15 and The last Guardian.

I donno, Nintendo's done a pretty damn good job on the Nx.

Hire ninjas, like Nintendo.

I just ignore every single rumor leading up to E3. Most of E3 was a complete surprise for me so far, and that's great. You don't have to go full blackout; just don't click every single rumor headline you see. Hell, just skim the gaming news for April and May and you should be fine. I just glanced at headlines and focused on existing games or what was already announced and all was well.

Pretty much. Even so, I found this E3 to be disappointing, especially compared to 2015.

Yeah, Sony and MS suffered some leaks. The Neo, Scorpio, GoW, and Spiderman. Nothing is ever fully safe.