Rivers hits his open receivers. The sad fact is he has not had many true talented wr#1's in his Charger career. He has one now and had one in Vjax. Talent is talent. Rivers has talent and so does Allen. I see great things in store if a talented #2 gets added. Floyd isn't it.
I disagree about Floyd, who has long been underappreciated, even by San Diego fans. When Floyd has been healthy over the years, he has been an excellent WR2. His aggregate numbers haven't been impressive because he has been injured a lot and because the Chargers #2 WR has typically been their #4 target, behind Gates, at least one RB, and the #1 WR.
Consider his PFF ratings going back to 2008:
2008 - +8.8 - WR#13 in 13 games
2009 - +16.9 - WR#7 in 16 games
2010 - +9.9 - WR#6 in 11 games
2011 - +14.2 - WR#8 in 12 games
2012 - +10.7 - WR#22 in 14 games
2013 - +3.6 - WR#55 in 2 games
PFF's rating is a cumulative metric, so to have been consistently high in their ratings is impressive, given that he has typically missed games every season. And I believe Floyd has typically ranked favorably in other advanced stats (e.g., yards per target).
Floyd is a veteran who has been with the Chargers since 2004, Rivers' rookie year, and he and Rivers definitely have chemistry. If he stays healthy this year, he is a massive upgrade on what they had after Allen last season.