Samsung QS700F satellite speakers worth it?

I've recently bought a QS700F at a great deal using store credit plus a tax rebate.

I was originally planning on going the AVR + surrounds route but ended up going with the soundbar due to price.

Although the subwoofer is great and the soundbar isn't terrible, I'm a little disappointed with the overall sound quality, specially the supposed surround effect.

I haven't yet tried to optimize the placement because the system is intended for a house I'll be moving in soon, but I'm wondering if it's worth spending another 300€ to get the satellites?

Would they work as rear speakers? Can the bar actually handle more channels? Or should I return and go for a full AVR + Receiver? Or perhaps upgrade to a better soundbar?