No not a gatekeeper but that’s why he moved up he knew he wasn’t get a title shot for awhile. He had to go to the back of the line.
No, he did it cuz of weight issues. He said it was too much to sacrafice when he's already been champion in that division and had like 20 fights in it, so he was gonna move up. At the time, he easily could have been back in the title picture, and sooner than he would at WW.
When he said he was gonna move up was still just ranked #4. The only people ahead of him were Eddie, and Khabib & Tony who were getting booked to fight each other. Justin & Dustin didn't really exist at the time. In his position, planning on earning a title shot would really have been as easy as beating just 2 of people like Barboza, Diaz, or Johnson, and maybe getting a shot at any of the guys above him.
It just so happens that Tony and Khabib would end up falling apart again and Conor would be stripped after 15 months of inactivity. And it just so happened that RDA had a perfect WW run, speeding him up to the interim title fight. I very much doubt he thought there was no way he'd beat Tony, Khabib, or Eddie, while also thinking he could run through people like Condit, Maia, Wonderboy, Lawler, & Woodley.