If anything, the league is a copycat league.
One or two teams have great success doing something different, and shortly thereafter you get several team trying to do the same things with hopes of duplicating that success.
The same is true of skill position players.
About 10-12 years ago BIG WR's started to show up in the league. Calvin Johnson epitomized the trend to bigger WR's. Everyone started looking for the next CJ.
To combat the evolution to big WR's, defenses started looking for BIG CB's. Defenders who could match up physically with the big WR's. Tit-for-tat/copy cat.
What I see offenses, yet again, morphing to in an effort to gain an edge over the ever changing defenses (trying to slow them down), is a blend of WR's body and skill types.
Teams are trending towards big/medium/small WR's to get the right personnel packages on the field to try and find ways to create mismatches against the defense.
Deep threats
Possession
Good YAC
ETC.
I don't think teams want all big, or all small, these days. It just doesn't fit with the multi-faceted types of offenses that are successful at the moment.
Green Bay has plenty of BIG WR's (Adams, Allison, Kumerow, MVS, ESB). Cobb was supposed to be that small slot/scat type WR but he fell flat after he got his big pay day. Some of it was injury related, but I think some of it was that "C" word we've been hearing about lately.
Packers need a smaller "slot" WR who can get YAC.
Look at the problems that Edelman presented for KC yesterday. It seemed nearly every time NE was faced with 3rd & 10, Edelman makes a big catch to get a new set of downs.
Being successful isn't just about throwing 40-50 yard bombs to a streaking BIG WR. It might be, visually, fun ........... but keeping the chains moving brings success. It might not be sexy, but it is proven. Just ask the Patriots.