That's why you make more than 1 character.
P.S. The lock picking perks are...bad.
Terrible answer. Although I am aware that being able to max every perk tree would be sort of lame, I do agree with the OP that 50 is a little, low of a number. I'm lucky that light armour perks are pretty bad, because personally I wanted a character who has some light armour perks (maybe maxed,) one-handed (this is what dual-wielding swords uses right?) along with destruction perks.
And I'm pretty sure you can't get 75 perks unless you literally do everything in the game, which kind of renders it useless because there would be hardly anything left to do when you achieve that.