The main reasons I'm optimistic is because:
A) We haven't seen HT back down on their Marvel team lineups so far and with GOTG being hot property at the moment, it will be a huge misfire to back down on 1 out of 5 members of the main team.
B) Unlike X-Men where we only got Charles as a cancelled prototype and Wolverine being the only consistent release, they've actually put out all the Guardians and showcased Drax with everyone else. With X-Men, the licensing with that property is also a whole different story in of itself.
C) HT could be taking their time with modding Drax. Alternatively, with the AOU hype building up, they're probably carefully deciding on when to put him up, just so that he won't seem underwhelming in comparison to all the other Marvel figures they've been putting out.
If we can get Thanos in the middle of all the AOU pre-orders, Drax should follow suit at some point.