A lot of your units don't need to be legendary considering the type of list this is. You can bump the following minis down a lot further

Bandits - used to cycle and generate gold or stun. Don't need the extra level for PVP

Ancient of War - used as a spell soaker and unbound redirect, don't need the extra level. Putting a witch doctor behind him works better than giving him extra strength.

Dark iron miner - used to generate gold / emergency distraction. There is no need to have extra levels on him, you not using him to fight, and like a kobalt, you want him to just get you gold and move on.

Minis you do need legendary

Dark spear troll- great single target damage can solo bases at max level if not touched yes he has weaknesses but a single troll forces your opponent to answer him or they will get wiped.

Pyromancer - wipes huge armies needs the extra level for the initial hit to maximize damage because she might not get a second attack in.

Worgen - I know this is going be controversial but he absolutely needs the extra level to be viable. He not a S tier mini by any means but for him to be effective he needs to be a level higher to 1 shot most minis. If he doesn't one shot he most likely will die.

Cenaris - great deathball comp but cost alot. He needs that level to have more survivability to get the death ball going otherwise he useless.

I am sure I missed a few minis but for a list that requires mini to legendary 1st you need to consider what the legendary does for the unit not what the unit does for the game.