i think that is a great idea. it would help kick start players at the start of the next level instead of just grueling training to earn a little gold, but the rewards should be smaller for lower levels and gradually get bigger with each 10 level increment.
Like they stated this would cause infimation (Not sure if i used the right word very tired)
If this were to be implimented i vote only for those lower lvls. Say 20 coin a lvl thats perfect its enough to get them kick started on abilities and skills and maybe some cheap armor. It wouldnt really matter to anyone over lvl 20 cause you make 20 coin every other kill.