Wouldn't surprise me. In fact, I'd say they're planning on it in the future.

Also of note, when they still had it on Tribble the missions limit was 8 missions. Published or unpublished. I suspect that they may have upped it to 10 on the Holodeck build if they are feeling generous.

But 8 is a healthy number to assume you have for total number of projects (until you try it!). But until they outline a specific plan, I think it's best to assume that any more mission slots might cost you something say in the C-Store like additional characters/ship slots.