Based on my experience, I would not break up the main shop with a tool room. We did that, and now I'd love to have that space back. Over time needs and treasures grow, but available space does not. On the farm we built a huge work shop able to swallow up a combine with the head attached if need be. Put an office in one corner with light storage above. Contains desk, recliner, TV, Fridge, bath, research library, etc. It's got AC and Heat unlike the rest of the shop. Now, over the years we've gotten: Tire changing machine, Industrial metal lathe, motorcycle lift table, 4x8 plate steel work table, parts washer and few hot water pressure washers, 54" table saw, RAS, jointer, 5hp planer, etc etc etc. They are all big and all take up floor space. What used to be huge, now barely accommodates a pickup.
Now, if you build a tool room outside the shop, that could be a great idea!
There are many narrow tool storage solutions that won't eat up your floor space like a tool room will, and as some have said, don't forget to look up for storage solutions.