I'm always wary to post in these threads, because....
1) I don't have time/energy to list every single mod that fits your criteria. (there would be so many)
2) It's very easy to find these mods yourself on PES or with ES Search.
3) Based on comments, votes, pictures, and modder reputation, you can
usually tell if a mod is Lore friendly or not, or if it's well balanced. (or if it's garbage)
There are also many guides that can help you make decisions. They are great for weeding out the not-so-good mods.
http://www.mwmythicmods.com/Gluby/Gluby_Main.htm - covers a lot of the gameplay and balance mods. As well as other aspects.
http://www.mwmythicmods.com/realism.htm - focuses on realism
http://www.gamesas.com/index.php?/topic/1155980-povuholos-tomorrowind-a-mod-recommendations-list-for-today/ - lots of great suggestions, including quests.
http://btb2.free.fr/morrowind.html - covers all topics
I will list a few of my favourite quests, to help get you started:
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=732
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=3242
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=3940
http://lovkullen.net/Emma/lokken.htm
http://lgnpc.org/home
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=7817 - perfect for new characters
http://www.gamesas.com/index.php?/topic/1060141-mod-recommendations-for-new-players/ - has more info on how to find all sorts of mods
Have fun!