build-up. It was his SON killing him, it had been foreshadowed earlier when Snoke said he'd have to face his father, and you could see it coming when Han went out on that bridge. But when I first watched TFA I still thought there was a chance that Kylo would do the right thing. Plus we talking about HAN SOLO - the dude we grew up watching and wanting to be, not new characters who we just met.
However, Han's death didn't really do anything for the plot besides move Kylo Ren further to the dark side. He didn't sacrifice himself to save his friends. I do think that him dying was a final reconciliation with Leia though - before he left she told him to bring back their son, and he died for her trying to do just that.

The deaths in Rogue One were different though - they actually had a meaning of sacrifice. It seemed like each character died RIGHT after they did something needed to get the mission completed. Saw Gerrera died right after convincing Jyn to go forward on the mission with the rebels. Galen Erso died right after showing Cassian and the rest of the rebels who he really was, bringing them together for the cause. K-2SO died sacrificing himself to let Jyn and Cassian escape to get the plans. Bodhi Rook died RIGHT after getting the message out to the rebel fleet that they needed to get the shield down to transmit the plans. Chirrut and Baze died RIGHT after hitting the switch to boost the signal for the transmission of the plans. Then Jyn and Cassian died right after they successfully transmitted the plans.

So it's not that the Rogue One deaths meant "more" or "less" than Han's death, but they were handled in a different way, and RO did a GREAT job of making us feel for the deaths of characters we had just met while TFA didn't have to do this because Han was a character we grew up loving.