Newbie nuker

Hey guys i am new here and also to dota 2...never played orignal dota though.
& totally new to MMORPG BTW a semi pro 1.6 player.

I just started dota 2 few months bac. i realized it was not like cs where reflexes play an imp role.
i feel dota is more of a common sense game.
pls take some time to read my boring story jst to get an fair idea of my gameplay style
I started off with undying...failed at last hitting so left it
then i saw ursa pubstomping with a massive 32-0 score with all his allies disconnected..tried him still failed
i stared seeing purge's videos...learnt most of mechanics
then i played pudge after watching dendi...played with it for weeks & literally dominated some games
somehow i am really good at hook...after playing with some pro's i realized that pudge's combo hook-rot-dismember didnt actually finished opponents even with decent item build.
Then i turned my eyes to invoker who is officially the most difficult hero to master
surprisingly whenever i picked invoker i had some strong support players with me so dominated most of invoker games with sunstrike...but then too he was squishy & gets killed easily
i saw a hero named tinker...then name attracted me ...i watched his skills & fell in love with his rearm ability.Dominated 100% of games with tinker & a unfair item named DAGON
Using the same strategy as tinker is made to be played "nuke-return-rearm-return-nuke"...& so it continued...but i observed if the game extended with all heroes at level 25 , tinker was squishy
Moved to experiment with next hero which was leshrac
now Leshrac was the one who was perfectly called crowd controller...i just pawned the game with leshrac's pulse nova & melted towers with diabolic edict...with pulse nova on creep stacks i had a significant gold advantage....until that son of b*tch silencer with his new last word spawned.
I am good at nuking & hate support heroes even though leshrac is one of them
please suggest some PRO tips for invoker,leshrac,tinker
i wud also luv to mess around with unusual item build of these guyz

If you want you can watch this replay of me playing invoker:
https://dotabuff.com/matches/82419030

The enemies were not really good and i got really far ahead, so i built Black King Bar and Desolator to play as a carry. (usually you should get agha or sheepstick as invoker :) )

I used the Exort/Quas build, where you rush 4 points of exort and 4 points of quas so you can summon 2 fire spirits at level 10. Combined with Cold Snap most heroes won't stand a chance against you 1v1 or in some situations even 2v1 at this point of the game. (cold snap+spirits means perma stun and Alacrity gives you even more mini stuns and dps) With Exort orbs and 2 spirits you will deal rightclick damage like crazy.
As the game drags on and you are not feeded and kill everthing with 3-4 hits, you of course should use all of your spells :D
If you want some teamfight potential, you should rather play Wex-based Invoker, but if you lack a good semi-carry or your teams needs pushing power, the exort/quas build is really good choice

Oh reflexes play an important role alright, it's more subtle than CS since you don't see it with inexperienced eyes but it makes the biggest difference. It's more about mind-games than the straight-up "pop headshot" kind of deal you see in CS, how you react to the situation is more dominant.

Indeed, twitch shooters are pretty obvious about reflexes, even to an untrained eye, but once you play a hero that requires good microing skills or someone who has more then the standard QWER spell setup then you'll see there is actually more reflex in an RTS game then an FPS game. This reflex is more in hotkeys then the actual mouse / controller. From what you're saying it seems you're looking to play more challenging heroes, and if you're open to expanding your hero pallet further then tinker/invoker/leshrac, then I suggest even more challenging heroes like Chen or Enchantress.

Reflexes do matter, but how much depends on which hero you're playing - try Weaver or Puck where you need fast fingers to survive and prosper. Certainly though it's as much about mental agility and sense than pure twitch - making the wrong decisions very quickly won't help you!

The thing with nukers is that almost all of them are to some degree support heroes (usually semi-carry/semi-support), and they all diminish as the game goes late. Right click damage scales in DOTA, nukes don't. You might want to try Luna or Shadow Fiend, they're both a mix of nuker and carry.