Question

Is Dubwool good to take to battle the champion?

Answer 1

While Dubwool definitely isn't the greatest Pokemon, if you're just battling the champion in-game you shouldn't experience too much difficulty as long as you are at a high enough level. A moveset with Cotton Guard + Body Press in particular should be able to beat most of his mons (apart from Aegislash obviously), though really in-game any Pokemon can carry.

If you want the best team to fight Leon, drop Dubwool, but if you like it and find it fun then by all means keep it. There aren't any bad Pokemon when it comes to in-game.

Answer 2

No
First, dubwool doesn't have great stats. It has good defense stats, but average attack and speed. Second, its moves aren't great. For coverage, all it gets are body press wild charge and zen headbutt. Third, it doesn't have an advantage against any of his Pokemon since it's a normal type.