I ran about 16 years with 2 subs behind me in the rear corners of the room with no localization issues; this was a pair of TN1220HO subs. They were a good 15' from the listening position.
Now, I have the twin TN1220HO subs on the front wall at 1/4 and 3/4 positions, and a pair of VTF-15H Mk2 subs on the rear wall at 1/4 and 3/4 positions.
A sub behind the listener is more common than you'd think if people put the sub where it works best instead of what looks best... If you place a sub based on looks, you're pretty likely to end up with sub-par bass; pardon the pun.
No! Try not... Do, or do not... There is no try.