For PS4 free to play titles it will be the Dev/Publishers decision whether or not to put their game behind the play station plus pay wall. DC Universe online, Planetside 2, Warframe, and Blacklight Retribution are confirmed to not require Play Station Plus.
[url=http://www.ign.com/articles/2013/06/13/ps4-publishers-decide-if-free-to-play-needs-ps-plus]Source.[/url]
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But that doesn't really make sense. It's not like you pay the Ps+ fee for every game that requires it. You only pay it once for every game. Essentially, if you only play one game that needs ps+, you're wasting your money.