Mending and its cost tweaks

Mending is one of the best enchantments in the game, but once you got a xp farm then you can repair any items infinite times and i think its just simple with less fun and excitement.

Some things that making enchanting less excitement:

1. Master villagers can trade diamond tools and gear (basically get diamond without caving)

2. Cost of repairing is always same ( i mean always same amount of xp )

3. Level 30 enchantments are not optimized and easy to get

SO WHAT TO DO:(what i think)

1. About villagers : idk but its not fair that we can get diamond gears and tools like that

2. About cost : One you add mending to your gear and tool then the cost of repair (that is xp) should gradually increase, so it can become a little difficult every time you repair the health of  your gears and tools again and again. So the player can decide if he/she wants to repair the health (assuming he/she is at gradually increasing  stage) or make new set of gear and tools

2.5  (Because mending is treasure enchantment )

3. About enchantment table : Add 40 and 50 (or only one) enchantment level to enchantment table, which will consume more xp and always gives multiple enchantments rather then chance