Shyvana's Current Place in Balance

Hi forumites!

I recently got back into league for season 5 after a break of a few months, and I've been playing some old favorites. Mostly high damage bruisers like Tryndamere, Olaf, and Shyvana.

I've noticed however, that it seems tough for me to do much damage as Shyvana. Even on bot games I'm not breaking even on kills/deaths, and I can't win in a fight against mages like Syndra or fighters like Nasus.

Has Shyvana been considered weak lately, or is it something I'm doing? I'm mostly wondering about item builds, since I usually build tanky items and maybe a Guinsoo's Rageblade or Tiamat. I feel like I'm either not focusing on the right stats or some other such build issue.

Any thoughts? Please keep it constructive, and thanks for any help.