I do agree with Dave's point, that it does not seem possible for anyone to be able to manage 5000 or even 3000 fully sourced profiles, with well written biographies. When I hear of some wanting to upload their 10000 person database, I'm rather sure many, if not most of them are poorly sourced, if at all. Of course, I would expect much better quality from experienced genealogists, like Susan. Welcome to WikiTree, Susan!
But, and this is somewhat off-topic, I've often wondered why this technical limit is applied, why we require people to split them up. Wouldn't it be a very helpful improvement if the system would allow limiting filters on any GEDCOM, so that any GEDCOM could be imported, but only a limited selection of persons are available for import from that GEDCOM. I'd love for the system to see that a user has never imported a GEDCOM before, so only allows the first 25 to be selected, or some other selection of 25. If someone, with GEDCOM experience, wants to load a 10000 person GEDCOM, then allow it but only make the first 5000 available. Or allow other selection filters, such as only those persons matching up to 3 different surnames, plus their spouses and children. Or only those born within the 1800's, plus their spouses and children. Or only those within 3 degrees of a specified name. Or only 200 persons, beginning at the 1300th person. Etc, etc... Then the same GEDCOM can be reused over and over, applying different selections, no splitting needed. (It might be nice to limit all selections to maybe 200 persons at most, per session.)