No one is forcing anyone to watch this, and for the record, I liked it, but with all due respect, if you feel the need to trash it, then you really need to watch it first.
It is all completely fine. Han Solo's childhood crush is working for someone, who is working for that person, but Han will never get to know anything about that. As far as Han is concerned, the bad guy gets killed, the girl is saved, and he wins the Millennium Falcon from Lando.
Also, I'm still unsure about this "10 years earlier" business. They obviously wanted to leave room for a sequel, but in reality, Rogue One could happen on the following day.