Okay, here is something that REALLY bothers me about the Star Wars films. More than Jar-Jar. More than probably anything else, even though it is a seemingly minor detail.
R2-D2 and C-3PO do not belong in ANY of the prequel trilogy films or Rogue One. Neither does Chewbacca, but I can tolerate his presence in ROTS because it sort of makes sense that he could have been at the battle of Kashyyyk. But still, I prefer to think he was more of a solitary rogue even at that point, because it better suits the character that was portrayed in the OT and beyond. But anyway, the droids do not belong in the PT or R1. Or if they were portrayed there, their appearances should have been brief and minor. There was plenty of other fan service and plenty of other callbacks. We didn't need the stupid droids.
Perhaps the most important reason is that, in the OT, neither Obi Wan nor Vader appear to recognize the droids. The EXTENSIVE and rather intimate interaction the two had with those two droids in the PT just doesn't make sense and appears to obviously retconned that it takes me out of the moment almost whenever they are onscreen in the PT. Second, their interaction and character arcs in the OT don't really make much sense given the extent of their close interaction with one another in the PT. Third, as I alluded to above, their presence in the PT was completely unnecessary.
As far as R1, I think they actually should have been in that film, but just not where they were placed. There is no evidence that Leia or the Tantive IV were on Yavin 4 at any point during the events in R1. Therefore, the droids shouldn't have been there. If they were to be given a cameo in that movie, it should have been at the end aboard the Tantive IV when the plans are given to Leia. Yeah, there could be any number of ways in which they actually got from Yavin 4 to the Tantive IV in the interim. But the events that occur between the time we see the droids and the time the battle of Scarif occur in such a rapid-fire manner in such a short period of time that it would seem very odd for the droids to have been picked up and taken along, which leads some of us in the audience to stop and have to think about how it could have happened and how unlikely it would be. And, IMO, if it is likely that the audience will do that, then the storytellers haven't done a good job. And that brings me to another problem altogether that I had with an otherwise stellar R1. The Tantive IV shouldn't have been there to begin with. It wasn't a war ship, and Leia was too important a leader to have been present at a battle that was likely to be a suicide mission or at the very least result in HEAVY casualties for the rebellion. They could have done the ending sequence basically the same, but had it be some other ship. That other ship beams the plans away just as Vader kills the person who did it. The Imperials then look at the ship's computers and determine that the plans were beamed to the Tantive IV and are able to ascertain its location from the transmission, and have a line about jumping to hyperspace to immediately pursue it near Tatooine. THEN it should cut to the scene were Leia is given the plans and delivers her "hope" line, with the droids present, if necessary. That would be a much cleaner way to do it and still bridge us directly to the opening of Ep. IV.
/rant