In my opinion, FastPass+ being free was better.
I think today with the paid Genie+ folks feel obligated to use their LL whereas with FastPass+, being free, folks commonly skipped their FastPass+ if they wanted to. I think this resulted lower standby wait times.
I think Genie+ really fails when it's really busy in the parks.
No matter what system is in use, it will always be true there are not enough attractions to absorb the crowds.
Until recently I never realized how much money TWDC Throws away on D+ content and Box office flops "in hope they may make money"
In my opinion the money could be put to better use to add attractions to the theme parks to improve the guest experience in a division that actually makes money.
Having said that. Disney knows, they need not improve the guest experience in the parks. Folks show up anyway.