Bulkheads make a lot of sense from a safety standpoint. If you don't have bulkheads you need to thing long and hard about alternate flotation methods.

If you go with bulkheads without hatches you might consider venting the closed compartments somehow. Some people have had problems with positive and negative air pressure buildups stressing their decks.

I'm thinking about (on my next boat) putting one bulkhead in front of my feet and one about 18" behind the cockpit. That gives storage without cutting holes in the deck. I haven't completely resolved the issues of dumping water out of the cockpit with the rear bulkhead that far behind the opening. I could put a bulkhead immediately behind the seat and put a screw in hatch in the bulkhead.