...reduce the cost of combining gems so that it only requires two gems instead of three (up to Flawless Square)...This will occur in patch 1.0.3. I took this to mean that it will only take two to make something of Flawless Square quality or below. For an individual tier, this isn't a big deal, but as you work your way up to Flawless Square it becomes rather significant.
|Number of Chipped gems to make...|
|Gem||New Count||Old Count|
As you can see this is a pretty significant change. After a few tiers the difference becomes great. For example: 9 chipped gems would just make you a regular gem in the current system, but would make a flawless gem in the post patch system and leave you 1 chipped gem. That's an extra upgrade with a chipped left over.
The potential gains that you can achieve by waiting until the patch to combine gems. Blizzard is making this change partly because it's most cost effective to just sell chipped gems instead of combining them to make higher gems to sell on the auction house. However, the price has also tanked so they're basically selling at vendor price, defeating the purpose. Making it easier to make higher level gems will hopefully rectify this situation. I'd be willing to bet that if this change isn't significant enough that they'll push this change up to higher tiers as well.
So I'll just wait until the patch to combine my gems thank you very much.
UPDATE: In addition to lowering the number of gems needed to combine, they are also drastically reducing the associated gold cost to combine gems at these levels. Relevant post here.