to fandom user 68.149.34.239 this thread is titled legendary skill, not legendary difficulty.
However, I can address your finding Legendary difficulty hard. I play on Legendary, but my bow does over 7 times the physical damage of your bow(less enchantment damage, but more consistent than chaos). On legendary, enemies do 3x damage to you while you do 1/4 damage to them(versus 2x and 1/2 on Master). So the physical damage on your bow is only 35 standard and 107 sneaking. The shock enchant is only 28. My bow does 1056 with steel arrows(3168 sneaking) and 99 each fire and shock. In reality, I'm doing 264 and 24/24 standard(maybe plus 2 for burn from fire) and 792 physical sneaking. My swords do 810 physical(202) and 99 fire and shock(24 and 24). My dagger is unenchanted dragonbone, but has a displayed damage of 292(73). With the 15x sneak perk, shrouded gloves, a power attack and savage strike in 1H, I can do 75x damage. I can one shot dragons(like legendary and serpentine) and one shot Karstag(but not consistently). I also generally have my armor above the cap and am at or near cap for both magical and elemental resistances. I still have close calls with legendary dragons.
I am contemplating a couple different builds for my next time or 2. One will use bound weapons(mystic bow, dual wield mystic swords) and depend on sneak attacks to do over 200 damage at range(the shadow warrior perk should help in most cases, but some preliminary testing is showing both strangely high and low numbers on that bow in various circumstances) and closer to 300 damage with a dual wield power attack(need to test that too to see if the damage multipliers work like I think they might. Speculated formulas for dual wield damage have changed some online). The other build is an enchanter using destruction for ranged(destro potions nearly triple damage, maybe shalidor's insights for emergencies like dragon attacks on towns) and enchanted wooden swords(3 of them in different elemental combinations) for dual wielding(should proc 4x each attack) boosted by Solstheim dragon priest masks(and fire spells boosted by aspect of terror in illusion). Both builds may use potent storm atronachs to help out with dragon fights in the wilderness. I will keep a steel dagger(base 5 + 76.67 smithing x3 with 1H skill and perks times 1.1 from seeker of might is 269/4 or 67) and the ignite spell( ahzidal's ring of arcana) as backups for both builds when I switch from my normal gear to sneak and carry in nordic tombs and dwemer ruins(should still be able to one shot Karstag with that).
As to legendary skills, the fastest skill to level(depending on how fast your drive saves the game or loads a new area) without the resto potion glitch is telekinesis(alteration) fast traveling between markarth and riften. 15 to 100 in a single load screen. It has already been mentioned that Illusion can be leveled very quickly with the Harmony spell in a crowded place(I like the Riften market during daytime, but only after becoming thane so guards don't hassle me). The reason for leveling up(besides more perks) is for extra attribute points. I always shoot for level 151 or higher, 810 health and stamina, and 180+ magicka(up to 420 on my level 172 Imperial).
My Level 169 nord had 390 magicka and spent all 168 of her perks(roughly 2/3 of the total 251 perks you can get at level 252). Honestly, some of the higher level perks in certain trees aren't worth it(experimenter and purity in alchemy, top perk in archery, all weapon specialization perks in 1H and 2H, right side of speech tree, oblivion binding, intense flames, deep freeze, etcetera).