Why keep DF off of new content?

[Ashkendor]

*different strats*
over time there WILL be a standardized strat.

Not entirely true. Even now, T9 has different divebomb strategies, A1 has different ways to handle the split, and A4 has different strategies with who picks up the orbs. If people aren't on the same page, it creates problems.

Honestly, if Savage was in the Duty Finder most of what you'd find would be trolls, lazy people looking for free carries or bored people looking to waste some time and maybe see past the first phase. I'd wager 99% of DF groups would never get past Faust to even see the actual boss. The DPS check is real. You wouldn't find your progression raiders in there helping out because they're in statics. Besides which, even if you did somehow end up with that miracle 7/8 group that cleared it for you, all you'd get out of it is the page. No chests, just 1/4 of an accessory.

If it was in DF, all we'd hear is bitching. "Why do my parties always wipe on Faust??" "This is too hard, nerf pls!" "OMG why is the item level requirement so high??" Ultimately, the reason it's not on DF is because SE doesn't want it there. Whether or not they put it there in the future remains to be seen, but I wouldn't expect it anytime soon.