Yeah, you'd think they'd go with an already established, and I believe quite popular version of the character instead of starting from scratch.
Too much baggage and continuity. Wasn't Oliver actually married
to Chloe by the end of Smallville? So you'd have to explain where Allison Mack is and why Oliver has a new love interest. Plus, you'd have fans constantly wondering when Clark or Lex or the rest of the Super Friends gang were going to show up.
Better to start over with a clean slate.