The restriction to use varchar-fields with a max length of (not fully) 4K was (as far as I know) bound to the fact that especially the supported DBMS Oracle has had a limited datatype-portfolio.
Since Oracle 12c this restriction has gone so that even Oracle is now able to support 32k-varchar-fields.
I would like see this enhancement in GEN too because in other environments the developers, dbas ... report that this restriction to the 4k boundary can be really painfull.
From a first discussion with Dan Short I know that CA would like to see that blobs should be used as a kind of workaround. But I think (and the dbas here too) that this not a good idea.
So please vote for this request, thanks!