We were told the theme for RoM last year at EAPlay, so I'm guessing we'll get the repeat of that this year and get the theme of the upcoming GP. Probably also an expected release timeframe that's more specific than "before the end of September".
I think we might get some clips or more info about Nifty Knitting too along with a predicted release month.
What might also happen: possibly another Pride item patch (or a different CAS/BB content patch) and talk about the changes/additions to the game that the roadmap post talked about.
But yeah, as others said, EAPlay isn't only Sims and since EL is releasing this week, I wouldn't bet on TS4 having a major presence there this time.