I did something like this with two subs about 20 years ago. Due to the room layout, the front sub was near the right speaker. The other sub was in the rear, left corner with a, 11 millisecond delay.
It worked quite well except that there was, to one side of my sofa, a huge stone fireplace.
The only way to kill that nasty, side-to-side mode it created was to use an Auralex MAX-Wall with 2 panels that were stand mounted. That didn't eliminate it, but it took the edge off it. If I wasn't doing serious listening, I'd stow it in a closet.
My current room is an odd "U" shaped basement with the listening area at the bottom of the "U". With a good bit of treatment of the side walls and a lot of stuff in the rear to diffuse the back reflection (it's a LEDE room design), it's the best sounding room I've ever been in. I can't really find any pronounced, low bass modes walking around the room. Also, the concrete floor has thick padded carpet and the drop ceiling has fiberglass insulation in between the first floor's joists above it. Toward the front, it's a bit like a black hole above 300Hz and the rear reflections offer a nice bit of beneficial ambience. All the wall treatment to toward the front have heavy curtains in front of them which also pays some dividends in the low end. while I will be getting two more subs, given the way it sounds, they won't be in the rear.
In most other rooms, though, what you are talking about makes a lot of sense.
If you have the space and budget, you can place a dipole sub in front of a sealed sub to create a cardioid sub for the front. You will, though, see the best results with this if you need to have your subs out in the room rather than the corners. In a corner, you aren't going to see much benefit. It would, though, work like gangbusters in the 1/2 placement arrangement.