That's still 4 distinct parties + your party, and that's under a system that favours 2 parties and doesn't allow for much nuance between or with the parties.

STV would:

• Allow people to vote for who they want
• Allow parties to differentiate themselves behind a simple left/right spectrum
• Allow people to vote for different factions within a party
• Not punish independents

All of which would help differentiate the parties, which even by your own description are not the same unless you don't think Blairism has had any effect on the Labour party.