Whelp Fallout 4 is basically Skyrim with guns, and I'm being serious.
There isn't a level cap anymore, its basically like Skyrim's leveling system, you put points into your perks/skills until you max them out. So you can basically keep beefing up everything past the point of them even needing to be level'd.
And the storyline doesn't end after you beat the campaign. I'd be happy about this, but its probably going to pull a Skyrim where it expects you to be the main story first and then do everything else. Lets just hope that your actions will actually do something in the story this time around.