why some heroes have so much power creep just to screw over 99% of players ?

for example i remember fondly when shadow fiend needed a lot of skill to hit razes because the ability dealt 900 damage with only 4 skill points it was worth it but was not easy to do and his ultimate dealt insane damage but mostly only on close range , now his ultimate is a screen wide extremelly long disable , nowadays you can hit a target standing still with 2 razes easilly his Q also slows and deals 1140 damage if you hit 3 razes , it used to take skill to play it now its way easier but it still sucks at high rank dota , so why do they keep buffing his abilities that were allready extremelly strong instead of changing his passives into something that also requires skill but solves the problem the hero has at high level , because shadow fiend now is just a insane bullshit hero terrorizing low rank pubs being one of the most popular heroes while it is still barelly picked at high rank and tournments , and this applies to many heroes in dota , sniper , witch doctor and anti mage are a few who keep getting buffs to their strong skills intead of fixing the problems the hero inherently has .