I understand what you're saying,but combos alone aren't enough to make a character unique.
When Cassandra was introduced in Soul Calibur 2,she wasn't as similar to Sophitia as Pyrrha is in SCV.
Because when they added Cassandra,they weren't intending on replacing Sophitia with her.You can't say the same about Pyrrha,however.
I like Pyrrha,i love her personality.
Even though i like her mother more,if Pyrrha does return they'll have to change ALOT in her moveset.
That'll make it 4 completely different Sword+ Shield styles. (if we're counting Lizardman (Since he's winning over Aeon in the poll) and excluding Patroklos).