In the comments of the ps blog one of the editors(?) said ps+ wasn't going anywhere. I find it hard to believe they'd keep this system that gives you free games and not allow anyone to access them on a new console. Maybe it's reading to much into it or wishful thinking
but it makes sense to me.
To be fair, the service is just that..the service. They promised those games to work on PS3, not on every hardware after the PS3. Same as Vita with PSP/PSone games; not everything you own digitally through Plus/PSN can be played on it.
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In my case, no BC is no biggie; though I understand why some may be dissapointed. Heck, many were pissed off when Nintendo removed the GBA slot on the DSi..and that was years after the DS/DSlite was on the market or the Wii with GCN games; or even the same Sony when they removed PS2 BC. In this case, they haven't said anything yet; so who knows.
If anything I expect it like the Vita. Were a good chuck works; but mostly digital games.
The Gaikai-side of things, will keep an eye out. One thing I like on the Wii U/Miiverse is that the implementation in-games feels like Twitter; with quick messages/suggestions. While the community/browser side is more like a forum, were you can post pictures of specific areas of either screen, or just post/draw random things. Developers have also said that hey like it, as they can see more directly the reaction of people either postives or negatives; and even check for reported bugs/problems faster.
So; will depend on how well it's implemented. The PS3 had a big problem (at least to me) were eveything was disjointed (Home ,chat, online, gaming were all separate things of each other); so there was no feel of community with anything online related.