Laguz are kind of oddballs really. In this game, you have far, far more characters than you're going to use. You have around 60 characters in 3 groups (Part 4). Before that, Laguz aren't very viable. They start out at ~ lv 10-20 on tier 2 (Laguz have no tier 1, to say it that was), so they should pretty much match your Beorc levels when Part 4 starts. Before that, it's Beorc all the way.
But in Part 4, they're not that much of a waste. They get roughly the same amount of exp as your Beorc, and you're generally on the offensive side (Laguz are great at offense, as you can decide when to attack, but not so good on defense, as they're not always going to be shapeshifted.
Well, that's not really the point. You're going to be using a good 30-40 units here. You'll only be able to take 17, and only 11 of your choice to the endgame. So half of the units you use are going to get ditched. Thus, it's not essential that all your characters would "turn out good". Being good at that moment is more important.
When I write Fact: in one part of the post, and opinion: (or a similar word), it's not because I can then say "my opinion can't be wrong". It is to inform what part is pure facts, and which part I try to draw a conclusion in.
