It make sense, you get more skilled in combat, and so, your blows are more efective and do more damage. And same for every npc/monster. What i thought about is that with every ood level up you gain a d10 of damage, and with every even you get 5 flat damage. So for example a level 3 would do 2d10 5, a level 10 would do 5 d10 25.

I think in this way leveling up would be more meaningful, and it already happens with the hp.

But I'm not a very exoerienced dm, so you think this could destroy the balance of the game too much? For example, spells are very powerfull already. Maybe I should double all hp? As for the monsters I'm thinking of using their cr as their level to calculate.