4500 people in a database is not excessive. What the previous post had in mind was if you were a collector and had merged tens of thousand people into your database.
I assume you have been working on your family for some time so the number of people in your database has not significantly changed in some time. maybe a growth rate of a half dozen people ever several months. This size database can easily be handled by FTM.
If you are planning on merging everyone tree and taking your family genealogy back to Adam and Eve, (not your grand uncle and aunt, but the ones in the bible) then definitely keep separate database.
I have one database for both my wife's and my families. Having one database removes a lot of duplicate entries, in location, sources and in people..
If needed you can report out the subfamilies for specific cousins.