Yep, this definitely added some players. I only had time to look at a few teams because I wanted to install the D&B V2 OF (which worked without issues), but I saw Wilshere & Bischoff on the Gunners, the Da Silva twins (listed as "Rafael" & "Fabio" in the game), Manucho & a few others on ManU and noticed that many of the teams seemed to have fewer 'unregistered' spots.
It also replaced the green & white/gold Adidas Tunit boots with the black/gold and white/red models. No new Nikes, Pumas or any new additions. I hadn't thought of it before, but I guess there isn't a boot editor as in years past. Not that boots are a big deal, but I wish that we could choose the model then select the color(s) from the palette. I'd love to have Bendtner's pinks so I could blame them when I shoot wide from 5yds with him...
It also updates transfers through the previous window for those who can't get option files. For those who can, V2 of the D&B Elite file updates them as of 1/19 (although I noticed L. Diarra is still on Pompey). Saw some new faces & appearance edits as well with the updated OF, including a pretty darn good one for Carlos Vela (are you listening Acid?) who had looked rather rodent-like by default. It kind of sucked for me though as I had done a good bit of editing on my own for Arsenal that I lost -- and a warning to Gooners, for some strange reason the 'kit style' for all Arsenal players was set to short-sleeves for some strange reason (in D&B V2, not the Konami update).
Now for the bad news: it does look like you lose CAPs after installing the data update. I had made a decent enough looking one for Wilshere that was infinitely better than the one Konami gave him which was gone after the data update ( and before the OF). Unfortunately I didn't record the build for it, so I'll have to try it again.
And finally, in all my excitement to browse the new stuff, I didn't actually play a game.
I think someone at PESgaming said that they noticed some gameplay differences, but didn't offer specifics. Here was the Konami
PR for the update (announced in October) which doesn't seem to indicate that there were any gameplay tweaks: