If the problems you have with Angel Beats are as you say, Little Busters! should not present you with the same problems, because it's longgggg. If you like the characters, you will be invested in them and in their routes. And I think the characters in Little Busters! have a good dynamic.
But that's just the thing, if you don't like the characters, you're doomed. And I can't possibly guess if you'll like them or not. So... look at the tags, or maybe watch a video of some characters, or something, if you are so thoroughly undecided. (NOTE: CLANNAD the VN suffers a bit from a problem early Key had, which is, the characters don't interact a lot amongst themselves except for a few routes. The Anime fixed this, and Little Busters! is the exact opposite of this)
If you liked the After Story, expect the true route in this VN to be different from the rest of the routes, as After Story was to the rest of the Visual Novel.
(Also, the music in this game is great. If nothing else, let that sway you)