Troop experience. Is it necessary or not?

1. I disagree with the fact that experience is given more to creatures of lower levels; it should be the other way around (logically).

2. I disagree with the doubling of combat effectiveness after level 10; such a property should not exist at all.

And provide a description of what and how is added for each level. (I won't vote until I see the description, and if I do vote, it will be with changes regarding the experience of creatures).