I have two basic questions regarding enchanted staffs:

First, will using it increase your skill ? Example, using conjure atronach staff will improve conjuration skill?

Second, can enchanted staffs be improved/upgraded ? The way we can upgrade enchanted weapons using the Arcane smithing skill?

Thanks for your replies!

to answer is No to both questions

Same as above answer. But if charge your staffs will increase your conjuration skill slightly.

However if you had dragonborn dlc and use staffs enchanter it will be determined by your respective magic skill. For example if your destruction skill is less than 50 you will be able to craft staff of chain lightning but not staff of thunderbolt.

Staves is one thing I really wish TES will change for the next game. Instead of having a "Staff of XXXX" they could have staves devoted to each school of magic that make any spells cast either have a stronger effect or cost less (or both). Playing mages is fun but needing to recharge a staff all the time is a waste since you can cast the same spell and have your magika automatically replenish itself.

*I'd also love to see the implementation of wands, rods, etc like in D&D.