We have seen a couple of iterations of dawnbreaker, but the current version is beyond broken.
She can and should be first picked in every game. If she is countered as a core, then you have a high damage, lane dominating, tanky, team fighting, healing, global support.
I cant remember seeing a hero in the last years dominating so many pro games, as dawnbreaker has been doing in recent months.
I have seen her popping off, one shotting heroes left and right, especially her deso, shard + blink timing is insane.
We saw in the last dpc, and now in this tournament, she is going +15-1 KD almost every game she is playing, and makes the gameplay very simple.
I know some versions of heroes have been busted, but for me, i dont think ive seen a hero pop off as consistently as dawnbreaker, holy shit.
I dont really know which way valve will nerf her. If they want to keep her as a flexible hybrid hero, or if they want a more specific direction for the hero, but i am expecting big nerfs.
Source: https://www.reddit.com/r/DotA2/comments/w4k2ie/i_cant_believe_how_busted_dawnbreaker_is/