A lovely hypothesis, Don, but how does a universe where gravity is a strong enough force to have consequence on the microscale level avoid collapsing into a singularity? Our own universe occupies space because the electro-weak force, which bonds matter into atoms, has both attractant and repellent aspects. The same force which causes an electron to revolve around an atomic nucleus (attraction) keeps the individual protons in that nucleus from actually touching each other (repulsion). This means that all things in our universe, other than extremely dense bodies like black holes and neutron stars, are mostly space with a small percentage of actual matter.

Gravitation is only attractive. If the force of gravity were stronger than the electro-weak force, protons would be forced into direct contact with each other, resulting in a universe of all matter, no empty space. In other words, a singularity. For a universe with that strong a gravitational force to have a spatial dimension, (and your hypothesis seems to require that it have a spatial dimension, else it couldn't react with our universe on a large-scale basis) there would have to be a corresponding repellent aspect to gravity. In other words, anti-gravity.

If there were cross-dimensional leakage of hypergravitational force, it seems to me that it would be accompanied by a corresponding leakage of anti-gravitational force, and nobody's ever detected anything resembling anti-gravity in our universe.