I think the romance makes the show more interesting, but I wouldn't mind more adventure. I can see the romance building up to something really good for the season finally. There's more evidence of that in yesterday's episode. I'm thinking that though we're done with the romance and relationships for a while to me at least.
Speaking of yesterday's episode:
From what I'm hearing the next episode's called "Time Sandwich" and it's focused on Magic Man and Finn and Jake going back in time to stop his shenanigans. If that's not actiony enough then I'm not sure what will satisfy some fans. http://adventuretime.wikia.com/wiki/Time_Sandwich