...

why?

Terminator 5 is being taken in a "new direction", yet they're still holding onto the novelty of a 65yr old action star who hasn't portrayed a convincing role in almost 20 years?

The TV series was great without him... T4 was decent without him, if you ignore the galaxy swallowing plot holes.

If Hollywood can "reimagine" a movies every 5-7 years (some better than others), then why is THIS still on life-support?

Technically he was in T4. So maybe it'll just be that sort of cameo.

I guess so, although I'm not entirely sure I would count a 1980s based CGI representation--with no lines. There are clever cameos, and then there's this. Hasn't that proverbial dead horse been beaten enough?

The Schwarzenegger horse, or the Terminator horse? The problem is their timeline--if they follow T4, the T-800 is the most widely used model.