Suggestions for a data-warehouse migration routine

I've ported enough of my companies database to Postgres to make
warehousing on PG a real possibility. I thought I would toss my data
migration architecture ideas out for the list to shoot apart..

1. Script on production server dumps the production database (MSSQL) to
a set of delimited text files.
2. Script on production server moves files via FTP to a Postgres
database server.
3. File Alteration Monitor trigger on PG server executes script when
last file is transferred.
4. Script on PG server drops the target database (by issuing a "dropdb"
command).
5. Script on PG server re-creates target database. (createdb command)
6. Script on PG server re-creates the tables.
7. Script on PG server issues COPY commands to import data.
8. Script on PG server indexes tables.
9. Script on PG server builds de-normalized reporting tables.
10. Script on PG server indexes the reporting tables.
11. Script on PG server creates needed reporting functions.
12. Vacuum analyze?

My question revolves around the drop/create for the database. Is their
significant downside to this approach? I'm taking this approach because
it is simpler from a scripting point of view to simply start from
scratch on each warehouse update. If I do not drop the database I would
need to delete the contents of each table and drop all indexes prior to
the COPY/data import. My assumption is all the table deletes and index
drops would be more expensive then just droping/re-creating the entire
database.

Also, is the Vacuum analyze step needed on a freshly minted database
where the indexes have all been newly created?

Thanks in advance for all feedback.

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