Some skills level more easy than others.....
TO easy (level 100 in 1 hour)
Mysticism
Restoration
Alteration
Illusion.
These can be trained SO easy and so fast... it's practically cheating... (only 8 cast spells for 1 level, others somewhat more time needed (20 per level)
still you avarage coffeebreak will do wonders...
Also TO easy (but need more active use)
Alchemy (you'd be surprised how many level's you rank on just the loot of a quick city-foot-raid)
Athletics & Acrobatics (I dont even seem to notice any difference, they level almost the same to me... auto run on (faster) and jump for even faster traveling.. just normal gaming and it goes quick.
Sneak (can be leveled on automatic, but just doing dungeons while on sneak-mode will level you fast already!)
Quite easy (but will take at least a little more time)
Block (easy to level, but slower to level.. you need to get hit.. and for that you need to be in combat)
Conjuration (it levels fast but it's casts are slower (you cant just keep c pressed) as an result you need to watch this over and will need to wait for your mana to recharge..
Light armor & heavy armour (will level a little slower than athletics&acrobratics will, still I find they level to fast..)
Speechcraft (levels quite fast, but will require a lot of active clicking... so prepare to have a sore wrist;))
Security (just your normaly breaking and entering will level you fast...
Armorer (easy if you keep your mind to it.. always carry on you some repairhammers, and repair ALL broken gear every fight.. (even the gear of fallen enemies that you might toss away after that to save weight..)
About right :
Destruction
Blade
Blunt
Hand-to-hand
Marksmanship
(all these require actual fighting and are only in real fights trainable.. and it will require quite a lot of hits to level. Even while you will use this in your normal play, it is much slower to level than the above skills, especially if you want to level all of them.. you will find yourself forced to wait with leveling up for a while every time..)
WAY to hard :
Mercentile : whitout training near impossible to level
so if I had my way :
Mysticism
Restoration
Alteration
Illusion.
would be made a lot harder to level (by a factor 15)
Alchemy
Athletics
Acrobatics
Sneak
would be made a lot harder tp level (by a factor 10)
Block
Light armor
heavy armour
Conjuration
Speechcraft
Security
Armorer
would be made a lot harder tp level (by a factor 5)
Mercentile
would be mad a lot easier (by a factor 10)
That would about balance it out.