Well, saying you need DSP EQ is kind of an oversimplification of measuring first, then treating, but the miniDSP units are very capable especially for subs. I would keep your sub and enhance with it.
Speakers vary by a great deal on what their ideal toe-in is. Focals for instance, to me sound best with zero to just a little toe-in. You can see in the measurements with some speakers that on axis they may have big peaks and valleys which get a lot smoother off axis. Toole was also probably thinking of less constrained rooms. Anyway, it's a total judgement call so try it and let me know if that's a good choice for you. As a long term solution though consider the GIK acoustics bass traps with diffusor panels. They will give you a sense of air and space while helping to focus the image and reduce bass standing waves.