Do you really need all of the sigals for a general RS-232 port?
Yes. Actually, a lot of RS-232 applications don't even use RTS/CTS anymore and have no hardware flow control at all - it is all done in software. Especially with the advent of virtual serial ports this is more the rule than the exception.

However, if you want to make a general RS-232 interface, RTS/CTS is smart to leave on there, just in case you are planning to attach a peripheral that uses it.