Why would we want this? I'd rather have 85 spells that level with me than 300 full of lesser/greater copies poluting my spell book.
Hey, I said that my Breton Mage would be happy with that not me.
He is a......collector of.....things, different things : small things, big things, shiny things and stupid things ( among those were all available spells ).
His greatest achievement was collecting everything in Vivek, Balmora and Sadrith Mora. That bastard took every item that could be taken and then stashed it all on his small, lovely, private island. It is needless to say that Morrowind was not the same place after the accomplishement of his devilish(

)plan.
What? You never rolplayed a pathological-maniac-wizard who did strange things in his virtual life instead of saving the world?

On topic:
50 spells for summoning including items( all creatures excluding bosses )
40 spells for destruction ( fire, ice, lightning, !runes! ) 10 spells for element(spray, bolts, balls, chains, storms, waves, rings) * 3 elements + 10 runes
40 spells for alteration( different protection spells : armors, shields, elemental shields, paralysis : pointed, chain, mass, water walking/breathing, opening(5 levels), transmutation(several variations for different materials), polymorph/petrify (single, mass)
40 spells for illusion( invisiblity(3 versions), light spells(pointed, following, small, huge), night vision, charming, frenzy/fear/control/calming( those must have several versions not only one like : singualar, mass, wave etc. )
30 spells for restoration ( wards(5), circles(5), different healing( self/other/slow/fast), anti-undead spells(both offensive and defensive), boosting spells(health/stamina/magicka), resistances(long but weak, short but strong).
That makes about 200 spells and most are useful. You can't say that different versions of same spell are useless. I agree that in previous games those were [censored] up but it doesn't mean that the concept is bad ( it is more about implementation ) and if you can remove spells from the spellbook then there is no problem with clutter. Obviously you can count some spells like one (all healing spells for instance) but I just count them separately and that increases the numbers. Maybe 300 was too much but 200 for a huge game like Skyrim doesn't seem inappropriate.