As a longtime Skylanders fan since before the first game even launched; this is great news.
The Skylanders series has always bounced between two devs, and each felt pretty disconnected from the previous game. Imaginators actually feels really robust, but the problem has been the lack of content I feel. The main game didn't seem to take as long as previous titles, but there is a lot of post game content in little mini challenge realms.
Adventure Packs have always given the game more life in a few hour extra campaign, but if there's more that's great.
One of the biggest things though will be how this effects Skylanders at retail. Many stores seem to be downgrading their Skylanders area, and some haven't even really had any stock since Christmas. In addition, lots of those adventure packs and other accessories seem to be hard to come by too. There needs to be more stock or maybe they need to sort out the distribution ratios on characters. In addition, they need to figure out about distribution of the new adventure packs. A few years back for Trap Team, one of the extra ones was released for a short period and then never again. As of now its still one of the rarest Skylanders sets and regularly appears on ebay and amazon at $100+ prices. There's no reason they can't print more of them.
For me personally, I usually pick up a majority of my figures during sales in the lead up to the new game since stores have to clear stock out. I probably wont get that chance but maybe they'll still have some decent enough sales through the spring and fall like usual.