I think the main problem is that the moment shields stop protecting ships from collisions, ramming becomes omnipresent tactics.
An easy fix to this (lore wise and mechanic wise) is that shields 'interact' with one another, creating powerful repulsion fields and thus reducing direct ramming damage. If you
really wanted to have fun with it:
Ramming in ships could result in shield damage
and shield generator damage from undue stress on the emitters due to the aforementioned interaction of fields on a large surface area. This means a ramming ship (with shield) is toasting its own shield generator, too, but could be engineering with module health for this exact tactic...at the expense of better shielding in non-ram situations.
For shieldless ships, ramming a shield would incur significant electrical and magnetic forces and, theoretically, could be very dangerous not just to the hull of the craft but internal modules. Ramming with a shield against a shieldless enemy could do universal module damage (i.e., like getting stuck in a Neutron Cone where all modules take damage slowly).
Point being, there's a way to balance that all out for the OP
and make it interesting
and add more depth to choosing shields and how they are engineered.