Seems we could have gotten a more fleshed out Phasma and a scene on the ship far exceeding what we got.
Sadly, Rian said it can't be so, and we got what we got.
I do like this alternative end to Phasma, it also gives Finn a chance to be a more serious character and less of the film's comic relief. HOWEVER, it reinforces a huge plot hole from TFA: If Phasma's armor can deflect laser blasts, why did she lower the shields on Starkiller Base? They wouldn't have hurt her. I re-watched the scene and Han DOES have his blaster aimed under her helmet at first, so sure, I buy that, but, when she's actually sat down and disabling the shields, Finn is stood a foot or two away aiming it AT her helmet.
I don't know if that's just me being being nit-picky, but still.
I can see why Rian Johnson chose the version of her death we got, as it doesn't reinforce the plot hole as obviously, but it was still in his film we learnt Phasma's armor and deflect blasts to begin with, so I see at as more of a fault with TLJ than TFA.