I think that it is up to TFB, and Activision here. After you 100% Skylanders games, you can play battle mode, or level up characters. But it starts to get into a Grind mode pretty quickly. From the looks of Disney's product having the Little Big Planet type of build and sharing of levels, this would give the game a much longer play time. And by that encourage more people to become collectors than casual players.
Time will tell but Activision is going to decide the future with the next game. Will it go WoW or Guitar Hero depends on if they can extend playtime past the core levels enough to satisfy.
Great observation. I think the potential of the technology looks better from Skylander's perspective. The freedom of not being tied to an IP is going to be both Activision's strength and weakness (and Disney conversely so). I actually think Infinity's "story mode" looks VERY weak as you can only use characters from that world...but it's in the game's "creative mode" that it really shines. Skylander's game is quite the opposite--and when the game is done it's basically some challenges and grinding on character levels. However each of the Disney worlds is distinct enough that I have to be vested in each and every franchise/world. Skylanders is infinite and there's no unique distinction between the character worlds.
Skylanders needs something else once "story mode" is done, or branching the adventure according to statistics recorded from the skylanders you use. They have the power to make the games VERY different than they are now...lots of untapped power. Mindcraft and now Infinity supports a Map Editor...we need to see this and multi-play capabilities in Skylanders asap (but a better spin on this).
From a collecting toy aspect---both franchises will do well for those customers who may not give a flip on actual gameplay because they are collecting the toys.