I think it's half and half. The Crystal Skull figures like Mutt, Irena and Dovchenko would be mostly for kids seeing the new movie; the characters from Raiders, Temple of Doom and Last Crusade meanwhile are targetted more at collectors in my opinion.
I think because, the Crystal Skull characters are from the new movie. After kids see the movie, if they like it, then they're going to want to buy the characters they just saw. The characters from the older films will most likely be trivial to them.
Longtime fans of the older films, meanwhile (I speak mostly for myself) will likely be interested in the characters from Raiders, Temple of Doom and Last Crusade, and want to buy them before they buy Crystal Skull characters.
Therefore in my opinion it's a toyline that's going out of its way to appeal to both kids and longtime adult fans alike, offering the same quality toys to both groups, and from what I saw of them at Wal-Mart today they're off to a great start. Sure, kids aren't interested in them
now, but after Crystal Skull comes out, dollars to donuts says they'll be snapping up the characters from that film in droves. I could be wrong about this, but, eh, the kid in me wants to believe that every kid likes the idea of owning plastic versions of characters they just saw in a movie they liked, and that kids will want to re-enact an Indy/Dovchenko fight the same way we, as kids, re-enated the Indy/Mechanic fight way back when....or wanted to, if you were like me and never got the toys;
born as I was in 1983, I missed the release of the vintage toyline, but grew up with the Indy films nevertheless, and I've spent my whole life wanting toys of them so I could redo this scene or that scene.
It's all dependent, of course, on whether enough parents actually take their kids to see Crystal Skull, and whether the kids actually wind up liking it. So here's hoping the movie is the hit we all want it to be, otherwise these toys (and the ones planned but yet to be released, like Henry Jones and Vogel for instance) will be all we grown-up fans will ever see for a long time.