There is a lot out there that says database size should not affect performance to any great degree. As long as indexes on tables fit in memory the database should remain performant.
However what is the reality? If the database architecture isn't the best, indexes don't fit in memory, and there is potentially a lot of redundant data are there significant gains to be made simply by deleting redundant data? I estimate that 60-80% of data in my database could be deleted.
I believe that reducing the database size and upping the RAM so that indexes can fit in memory would give a significant performance increase which would give some breathing room for a few months to rearchitect the system.
Are there also other factors such as IO, fragmentation, working dataset etc that affect performance based on database size?