It depends on the people working on said game and their history. If past games in a series have been great and the same people are developing the next iteration, then there is a very good chance their next game will be a hit. If it's a new IP, only established developers should be given the benefit of the doubt. Anyone else, I agree. It wouldn't be right to assume their game will be great based on what you said.
For example, MGSV will be superb even though I've only seen some trailers and not much else. Kojima is that godly. (btw apparently he is turning 50 but he still looks like he's in his goddamn thirties. I'm pretty sure he's immortal or something.)







