For me, even last season, the majority of my games where like that: Steamrolled, either for or against me. I just depended on what teammates I got randomized with.
I do agree that these changes seem to be pushing the game to make that scenario more likely, but I think its still too early to make a definite judgment.
People are learning lots of new stuff right now, between the rift herald, the new masteries, items etc. Heck, for the first 2 days, every game had 2+ adc's in it. Since then, its seemed to have mellowed out.
It is certain that there will be adjustments made by RIOT as the preseason continues. That is part of what the preseason is for: Throwing out major changes and seeing what happens and trying to balance it before the regular season starts.
TLDR- I think its too early to say exactly how these changes have effected the game, though I am concerned about the current state atm. Give it time (2 or 3 patches) and see what RIOT does. Its preseason. Have fun, learn, adapt, overcome, dominate!