On the surface it does sound like a good idea. But, things aren't that simple ;-{
First, the recall was more to do with bad GPU logic than heat.
As to just looking at this from a cooling perspective, while you do offer a bigger entry for the air to enter. You are altering the airflow patterns within the system. Your actions would cause the HD to overheat as their won't be enough airflow across it as the other pathway is less resistive. In addition it does open your system for things to enter which could cause problems (paper clips, staples or something spilled). I would recommend you leave the optical drive in.
This is not a good idea in the long run. So is there any way we can lower the systems heat? Yes!
The first thing you can do is retire your HD and put in its place a SSD. It will run much cooler than the HD.
The next thing is to monitor what apps you are running that are not needed when the system is running warm using Activity Monitor which you'll find in your Utility folder. And then last piece is a better way to monitor all of the thermal sensors you have in your system as well as the fans. I strongly recommend using TG Pro for less than $20 US its worth it. It also offers a way to boost the fans earlier than what SMC would boost them.
Well... I don't agree with the strange ways people have modified their systems. Yes, I've seen some really wacky ideas people have tried and championed as being the best. Apple did a good job in its design, its our misuse and not keeping the system clean of dirt & dust that is the bigger problem for most users.
The second issue is people often over stress their systems, laptops are not desktops!
While they can do some heavy processing, they are not designed for constant stress of running heavy gaming which they weren't designed to run. Think of it this way you wouldn't try using your Honda Civic running in the Indy 500 car race would you? You'd burnout the engine and transmission long before the end of the race.
Getting back to the internal air flows with the optical drive removed. Lets look at an air flow model:
Looking at this image lets say the air flows from A & B are 20k CFM's so the output C would be the max of 40k CFM's. Now lets say you altered the flow rate on A so now its 30k CFM's (remember the output is still 40k CFM's) then B flow rate would drop to 10k CFM's. If the area served by B needed more cooling it couldn't get it as the suction of the fan wouldn't have anyway to offer that area more cooler air. While this system has two fans, Apple didn't design them to be biased (SMC raises and lowers both fans at the same RPM).
Just for background I support two companies that use this series of MacBook Pro's. Combined, we support over 500 laptop systems. Yes, we encountered the GPU issue and we had the logic board replaced on over 30% of the systems. We also run some heavy CAD & graphics on these systems, we have not needed to alter the systems to the level you are proposing here.