The bass is already omnidirectional, but pole-mounting would give your mids and highs (which are directional) a "clearer shot" at people's ears, whether they are in the band or on the stage. The downside is, you would lose a lot of boundary reinforcement in the low end. Most bass cabs are designed with the expectation of there being at least one nearby reflective surface.
In my Hathor and Changeling cabs, I have tried do get some mids and highs up to the bass player's ears without having to resort to pole stands or tilt-back. The midrange cones are in a chamber that has big openings on the top, which bounces some of the cone's backwave energy up towards your ears. Probably not a perfect solution, but hopefully "better than nothing".
Some of my Thunderchild cabs have an optional rear-firing tweeter, which can help with that too, if there's a reflective surface behind the cab.