In a word, no the value will never jump up on Sideshow Star Wars figures. Some are more desirable than others and so may hold their value a bit better, but with very few exceptions they always go down in value.
I can only see it getting worse in the future. Not to be too much of a downer, but unless Lucas pulls something incredible out of his hat with the upcoming TV stuff, Star Wars as a phenomenon has peaked. I'm sure it'll last a long time, but it's probably all downhill from this point onward in terms of the number of fans willing to buy stuff like this. That means demand is only going to go down over time.
Also, think of what happened with the Hasbro figures after Sideshow took over the license. Collectors bought a lot of the mediocre-at-best Hasbro stuff, but once Sideshow's stuff came out, you couldn't give the Hasbro figures away. It's entirely possible that in 10 or 15 years another company will come along with stuff that makes today's Sideshow figures look like the Hasbro stuff did.
So in the near future, I can only see prices holding at the level they are now, or possibly going down. I suppose it's possible that they might get more valuable over the very long term, like 30+ years from now, but otherwise I just don't see it.
Personally, I think being patient and just waiting to buy everything on the secondary market is probably the best strategy. Heck, if you wait a while you can often find the non-exclusives on clearance.